The Broadband Radiometer (BBR) instrument on EarthCARE will provide measurements of the outgoing shortwave (SW) and longwave (LW) radiances at the Top of the Atmosphere (TOA) in an along-track configuration at three different viewing zenith angles (fore, aft and nadir observations). Radiative fluxes at the TOA are estimated from the BBR directional measurements through a radiance-to-flux conversion algorithm.

In this study, the methodology to estimate the thermal flux within the Level 2 BMA-FLX product from the BBR LW unfiltered radiances (from BM-RAD product) is presented.

The LW Angular models are obtained through multiple regressions on brightness temperatures and brightness temperature differences of the multispectral imager (MSI) 10.8 µm and 12 µm channels, and corresponding LW fluxes obtained by using a large database of LibRadtran and SBDART radiative transfer simulations.

The radiance to flux conversion algorithms are applied to each of the BBR views, which have been previously collocated at a reference level in order to minimize parallax effects. The derived fluxes from the collocated views are then combined into a single flux value at the reference level. In order to fulfill mission requirements, the TOA fluxes obtained should be consistent with an accuracy of 10 W m-2 for an instantaneous BBR Standard footprint of 10x10 km2. The estimated performance of the LW algorithm is about 3.5 W m-2 for the nadir view and of 1 W m-2 for the off-nadir view for plane parallel scenes and better than 8 W m-2 if tridimensional effects are taken into account.

Verification of the algorithms has been carried out using Cloud’s and the Earth’s Radiant Energy System (CERES) and Geostationary Earth Radiation Budget (GERB) data: (i) by using a dataset of collocated CERES and GERB-like/SEVIRI data, (ii) by applying the ADMs to CERES radiances and comparing the resulting fluxes with those obtained by CERES (iii) by using a True Along Track MODIS/CERES dataset for the validation of the combination of the 3-views fluxes.

The reduction of the error in the flux when the 3-views are combined has also been assessed.

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The quiet sun brightness variability on the decadal to millennial timescales is highly debated since solar models produce contrasting results with variation from 0.1 W/m² to 6 W/m² since the Maunder minimum (1645-1715).

A TSI satellite database is available since 1978 but it is made of several records covering different periods since 1978. The most relevant ones are: SMM/ACRIM I (1980 - 1989), UARS/ACRIM II (1991 - 2001) and ACRIMSAT/ACRIM III (1999 - 2013), Nimbus7/ERB (1978- 1993), ERBS/ERBE (1984 - 2003), SOHO/VIRGO (1996-present), SORCE/TIM (2003-present). Several TSI satellite composites have been proposed. The most popular ones are: ACRIM; PMOD; RMIB; Dudok de Wit et al. (2017). Although these composites use different sets of TSI satellite records and merging methodologies, they are relatively equivalent since about 1992, the beginning of the ACRIM II record, because they could be based on high quality TSI records. On the contrary, a large uncertainty exists in the TSI composites during the period from 1978 to 1992. A major source of uncertainty is due to the fact that the ACRIM II mission was delayed due to the Space Shuttle Challenger disaster on January 28, 1986, which prevented this record to overlap with the ACRIM I record ending in July, 1989 (1989.53). Thus, there is an ACRIM-gap (1989.53-1991.76) that prevents a direct cross-calibration between the two high quality ACRIM I and II TSI records. During the ACRIM-gap only results from the lower quality TSI records produced by Nimbus7/ERB and ERB/ERBE are available. The quality of these TSI observations was limited by a lack of degradation self-calibration capability and a lack of independent solar pointing. The main issue is that during the ACRIM-gap Nimbus7/ERB and ERB/ERBE records appear to be incompatible with each other with the former trending up and the later trending down. This problem yielded to an uncertainty regarding whether TSI increased from 1980 to 2000 (e.g. ACRIM), as also the global surface temperature of the Earth did, or not (e.g. PMOD). The issue remains open because experimental evidences seems to suggest a plausibility of the Nimbus7/ERB upward trending during the ACRIM-gap (Scafetta, N., R.C. Willson, GRL 36, L05701, 2009; Scafetta, N., R.C. Willson, Astrophysics and Space Science 350(2), 421-442, 2014 ).

Total solar irradiance (TSI) proxy and semi-empirical models have been also used to reconstruct TSI variations. They well agree with the TSI composites for the period after 1996. However, a progressive divergence is observed in the early period (e.g.: 1981-1996) of the data suggesting that the relation between TSI and the proxies used for the reconstruction is not stationary, and the proxy models have different scaling errors between the early and later periods. As a result, the TSI proxy models may be missing a slowly varying component of TSI variation.

In particular, we evaluate a number of currently proposed TSI proxy or semi-empirical models, including SATIRE and NRLTSI2. They appear to be reliable in reconstructing the fast fluctuations of TSI variability but fail to properly model longer time-scales. They agree with the TSI composites after 1996 but a progressive divergence is observed for the early period (e.g.: 1981-1996). In particular, the amplitude of the solar cycle from 1980 to 1992 appears significantly underestimated by the proxy models. This suggests that the relation between TSI and its used proxies is not stationary but varies in time. Perhaps their scaling errors also evolve in time. Because of the non-stationarity uncertainties in observation, these TSI models are likely missing a slowly varying TSI component that needs to be non-linearly coupled with the typical adopted solar proxies (SSN and SSA, MGII, F106, etc.) which may be more indicative of the active solar regions. Therefore, there is a need to develop better quiet sun brightness models since the proposed evidences indicate that it may vary significantly from cycle to cycle.

Herein we propose a correction to the TSI proxy models by empirically modeling their discrepancy with the TSI observations by applying polynomial regression functions and a Heaviside step function during the ACRIM-gap to the most reliable TSI satellite records. Our proposed statistical methodology suggests that the quiet sun brightness increased from the 1986 to 1996 TSI minima by ~0.45 W/m² reaching a peak in 2002 and decreased by ~0.15 W/m² from 1996 to 2008 TSI minima. This pattern is found compatible with the ACRIM TSI composite and with another recent TSI satellite composite made using the entire original experimental TSI database (Dudok de Wit et al., 2017).

The observed TSI pattern (a TSI increase from 1980 to 2000, and a decrease since 2000 which can continue up to 2030) also agrees well with the prediction of a solar model based on observed solar harmonics at he multi-decadal to millennial scales (Scafetta N., J. Atmospheric and Solar-Terrestrial Physics 80, 296-311, 2012; Scafetta, N., J. Atmospheric and Solar-Terrestrial Physics 81-82, 27-40, 2012 ).

Area B - Board 170

Understanding the physical origin of the solar and climate oscillations is of crucial importance. Herein we analysed recent literature showing that both kind of oscillations are closely related to each other and can be deduced from the solar system resonances. These oscillations can then be used to produce effective solar and climate forecast models.

In particular, I show that the Schwabe frequency band of the Zurich sunspot record since 1749 is found to be made of three major cycles with periods of about 9.98, 10.9 and 11.86 years. The side frequencies appear to be closely related to the spring tidal period of Jupiter and Saturn (range between 9.5 and 10.5 years, and median 9.93 years) and to the tidal sidereal period of Jupiter (about 11.86 years). The central cycle may be associated to a quasi-11-year solar dynamo cycle that appears to be approximately synchronized to the average of the two planetary frequencies.

A simplified harmonic constituent model based on the above two planetary tidal frequencies and on the exact dates of Jupiter and Saturn planetary tidal phases, plus a theoretically deduced 10.87-year central cycle reveals complex quasi-periodic interference/beat patterns. Its major beat periods occur at about 115, 61 and 130 years (Gleissberg oscillation), plus a quasi-millennial large beat cycle around 983 years (Eddy Oscillation). A simple harmonic model based on the 9.98, 10.9 and 11.86 year oscillations hindcast reasonably well the known prolonged periods of low solar activity during the last millennium such as the Oort, Wolf, Sporer, Maunder and Dalton minima, as well as the seventeen 115-year long oscillations found in a detailed temperature reconstruction of the Northern Hemisphere covering the last 2000 years.

The millennial three-frequency beat cycle hindcasts equivalent solar and climate cycles for 12,000 years. Finally, the harmonic model herein proposed reconstructs the prolonged solar minima that occurred during 1900–1920 and 1960–1980 and the secular solar maxima around 1870–1890, 1940–1950 and 1995–2005 and a secular upward trending during the 20th century: this modulated trending agrees well with some solar proxy model, with the ACRIM TSI satellite composite and with the global surface temperature modulation since 1850 which can be accurately reconstructed using astronomical harmonics at 9.1, 10-11, 20, 60, 115 and 980 year. The model forecasts a new prolonged gran solar minimum during 2020–2045, produced by the combined minima of both the 61 and 115-year reconstructed cycles. Other discussions are added about the evidences of an infuence of the resonances of the solar system on solar activity explaining also the Jose (159-185 year), the Seuss (200-220 year) and Hallstatt (2100-2500 year) oscillations. All these oscillations can be deduced from stable solar resonances produced by Jupiter, Saturn, Uranus and Neptune. The demonstrated geometrical synchronicity between solar and climate data patterns with the proposed solar/planetary harmonic model rebuts a major critique (by Smythe and Eddy, 1977) of the theory of planetary influence on the Sun.

In addition, the period from 2000 to 2016 shows a modest warming trend that the advocates of the anthropogenic global warming theory have labeled as the "pause" or “hiatus.” These labels were chosen to indicate that the observed temperature standstill period results from an unforced internal fluctuation of the climate (e.g. by heat uptake of the deep ocean) that the computer climate models are claimed to occasionally reproduce without contradicting the anthropogenic global warming theory (AGWT) paradigm. Statistical analysis rejects such labels with a 95% confidence because the standstill period has lasted more than the 15 year period limit provided by the AGWT advocates themselves. Anyhow, the strong warming peak observed in 2015-2016, the "hottest year on record," gave the impression that the temperature standstill stopped in 2014, but temperature peak is unrelated to anthropogenic forcing because it simply emerged from the natural fast fluctuations of the climate associated to the El Niño–Southern Oscillation (ENSO) phenomenon. By removing the ENSO signature, the temperature trend from 2000 to 2016 clearly diverges from the general circulation model (GCM) simulations. By contrast, a semi-empirical climate model proposed in 2011 and 2013 by Scafetta, which are based on a specific set of natural climatic oscillations believed to be astronomically induced plus a significantly reduced anthropogenic contribution, agree far better with the latest observations.


References:

Scafetta, N., Mirandola, A., Bianchini, A., 2017. Natural climate variability, part 1: Observations versus the modeled predictions. International Journal of Heat and Technology, 35, Special Issue 1, S9-S17.
Scafetta, N., Mirandola, A., Bianchini, A., 2017. Natural climate variability, part 2: Interpretation of the post 2000 temperature standstill. International Journal of Heat and Technology, 35, Special Issue 1, S18-S26. DOI: 10.18280/ijht.35Sp0103.
Scafetta, N., Milani, F., Bianchini, A., Ortolani, S.: 2016. On the astronomical origin of the Hallstatt oscillation found in radiocarbon and climate records throughout the Holocene. Earth-Science Reviews 162, 24–43.
Scafetta, N., 2014. Discussion on the spectral coherence between planetary, solar and climate oscillations: a reply to some critiques. Astrophysics and Space Science 354, 275-299.
Scafetta, N., 2013. Discussion on climate oscillations: CMIP5 general circulation models versus a semiempirical harmonic model based on astronomical cycles. Earth-Science Reviews 126, 321-357.
Scafetta, N., 2012. Multi-scale harmonic model for solar and climate cyclical variation throughout the Holocene based on Jupiter-Saturn tidal frequencies plus the 11-year solar dynamo cycle. Journal of Atmospheric and Solar-Terrestrial Physics 80, 296-311.
Scafetta, N., 2012. Does the Sun work as a nuclear fusion amplifier of planetary tidal forcing? A proposal for a physical mechanism based on the mass-luminosity relation. Journal of Atmospheric and Solar-Terrestrial Physics 81-82, 27-40.

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Monitoring the Earth Radiation Budget (ERB) and Total Solar Irradiance (TSI) is of fundamental importance for understanding climate and its evolution. Historically, Wide Field Of View (WFOV) radiometers were used for monitoring ERB and TSI, then scanning radiometers replaced them, leading to an increase in resolution. Unfortunately, when using scanning radiometers, the Earth Energy Imbalance (EEI), which is the most direct indicator of climate change, can not be measured with sufficient accuracy. A differential measurement between the incoming solar radiation and the Earth’s total outgoing radiation is one possible solution to this problem. Using a WFOV radiometer could help to achieve this goal. We propose two innovations to improve the accuracy of the existing radiometers: (1) instead of using a monolithic cavity, we propose a segmented cavity, resulting in a reduction of the spatial non-uniformity, (2) to further reduce the error due to the non-uniformity, we propose to supplement the cavity with WFOV shortwave and longwave cameras.

In this article, a potential design of the segmented WFOV cavity radiometer will be presented. The radiometer will consist of metallic segments with high thermal conductance, mounted on thermally isolating feet relative to a thermostatic housing. Each segment behaves as a thermal capacitor in series with a thermal resistor, forming a first order thermal system. The temperature difference over the thermal resistor is measured with thermistors mounted in a Wheatstone bridge. The segments are coated with Vacuum Aligned Carbon Nanotubes having high absorptivity over a wide wavelength range (220 nm – 15 µm). Following the electrical substitution principle, each segment is also equipped with an electrical heater. The electrical power dissipated in the heater is regulated by a servo system that maintains a constant temperature difference over the thermal resistor. By choosing the gain of the servo system, the response time of the system can be improved at the expense of an amplification of the noise.

The field of view of the WFOV radiometer needs to be 135° to observe the Earth from limb to limb, from a typical low Earth orbit with height of 750 km. The baffle will consist of a precision aperture and one or more view limiting apertures. For additional accuracy a shutter will be foreseen – as it is commonly used in TSI radiometers – which will be sequentially opened and closed, allowing to remove thermal drifts. Two cavities will be foreseen. The first cavity is used for routine measurements and can be subject to ageing due to exposure to UV radiation. The second cavity will be used sporadically, such that its ageing is negligible and traceable. Comparisons between the two cavities will be used for the ageing correction of the first cavity. A first analysis of the radiometric performance will be described.

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The Sun-earth IMBAlance (SIMBA) satellite is a 3U satellite currently under construction with the participation of the Royal Meteorological Institute of Belgium, the University of Leuven and ISIS-Innovative Solutions In Space. By the time of the symposium we will be finishing up the last tests before launch.

The scientific payloads objectives are to study the feasibility to monitor with the same instrument both the incoming solar radiation and the earths outgoing radiation. To achieve this, the main payload sensor is an electrical substitution cavity radiometer designed for the absolute measurement of total radiation. The cavity radiometer is normally pointing towards the earth for a good sampling of the earths outgoing radiation and will be occasionally pointing towards deep space and the sun for calibration.

The earth’s outgoing radiation consists of emitted thermal radiation with wavelengths above 4 micrometer (longwave) and reflected solar radiation with wavelengths below 4 micrometer (shortwave). To separate the two different kinds of radiation emitted by the earth, the payload further consists of black and white flat spectral sensors.

The payload of the SIMBA project builds upon the experience of the Royal Meteorological Institute of Belgium with building space instruments for the measurement of the Total Solar Irradiance since 1983, and with the processing of the Geostationary Earth Radiation Budget data since 2003.

If the scientific goals are met, SIMBA and successors will contribute to the monitoring of the Essential Climate Variables of Total Solar Irradiance and the Earth Radiation Budget. As a long term objective, which will likely not be met by the first SIMBA satellite, this should lead to the direct measurement of the earth radiation imbalance. This long term objective is very challenging both in terms of instrument design, characterization and temporal and spatial sampling and at the very least requires measurement from a satellite constellation.

In this talk we will first discuss the general design of the SIMBA cubesat and the payload. Then we will adress the scientific goals and the choices made to reach them. We will then tackle the challenges met during the construction phase of the satellite. Finally, we will discuss the results of our test campaigns.

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Satellite based hyper spectral measurements enable comprehensive atmospheric data records, suitable for short term sensitivity, as well as long term monitoring and prediction studies of the Earth's radiation budget. To this scope, spatial and temporal uniformity and uncertainty source traceability are key elements to ensure stability and consistency in the data record.
This talk focuses on the practical aspects intrinsic to the development of a uniformly stable, accurate and global data record of atmospheric temperature and moisture - the two main contributors to Earth's outgoing longwave radiation - retrieved from satellite based hyper spectral sensors. We focus on the lessons learned from the NOAA Unique Combined Atmospheric Processing System (NUCAPS), the NOAA hyper spectral retrieval algorithm used to operationally generate atmospheric environmental data records from satellite-based hyperspectral sounders such as AIRS, IASI and CrIS. Retrieval sensitivity studies, skill and error characterization are used as metrics to illustrate important lessons learned ascertaining the applicability of satellite soundings for the above mentioned research applications. We show results from a sensitivity study during the 2016-2017 El Nino event. We will use sea surface temperature, temperature and water vapor profiles retrieved from SNPP CrIS and ATMS measurements, to assess the magnitude of the moistening anomaly in the upper troposphere and its radiative impact. This talk concludes with few guidelines aiming at indicating future algorithm development steps and re-processing plans that operational agencies might want to consider in order to improve the accuracy and long-term stability of satellite soundings data records suitable for Earth's radiation budget studies.

Area B - Board 174

Land Surface Temperature (LST) is an important quantity describing the interface between long- and shortwave radiation fluxes on one side and turbulent heat fluxes and the ground heat flux on the other side. Therefore, it is a useful parameter for tracing the impact of changing climatic conditions on our environment. Satellite derived LST are an indispensable tool for monitoring these changes consistently over large areas and for detecting long term trends and patterns. Thermal Infrared (TIR) data from the AVHRR (Advanced Very High Resolution Radiometer) sensors on NOAA-satellites are operationally available since the early 1980s at 1 km spatial resolution. Several algorithms exist to derive LST from top of atmosphere brightness temperatures, which requires accounting for the attenuation due to of water vapor and for effects from land surface emissivity and sensor degradation. In the TIMELINE project (www.timeline.dlr.de), one aim is to retrieve accurate and consistent LST for the entire operating period of AVHRR sensors over Europe using the approach created by Frey et al. (2017) based on the Qin et al. (2001) and Becker & Li (1990) algorithms.
In this study we present the validation results for the TIMELINE AVHRR LST product as well as preliminary analyses of patterns and trends in this multi-decadal data set. The validation approach consists of the following steps: a) an assessment of the consistency of the AVHRR LST time series between the different NOAA missions; b) an inter-comparison between AVHRR LST and in-situ LST obtained at 11 stations located in Europe (Evora, Donana), North America (7 surface radiation network (SURFRAD) stations) and Southern Africa (Gobabeb, Heimat); and c) a comparison of the AVHRR LST product to concurrent MODIS (Moderate Resolution Imaging Spectroradiometer) LST (MOD21 product). The comparisons were conducted on a daily basis for five different years (2000, 2010 - 2013). Only pixels satisfying a certain homogeneity criteria were selected. Furthermore, a maximum time difference of 10 minutes between AVHRR and MODIS acquisitions and in situ LST was permitted according to the suggestions from the CEOS LST Product Validation Best Practice Protocol. In total, 4000 in situ measurements and 1000 MODIS scenes were compared to the AVHRR LST product values.
First results indicate a successful derivation of stable LST time series from multi-decadal AVHRR data. The comparison between the TIMELINE LST product and the selected data sets show diurnal and annual patterns as well as differences for individual land cover types. For 2010, on average, an absolute deviation of the AVHRR LST by 1.5 K from in situ LST as well as a difference of in average 1.5 K from the MODIS product was observed.

Area B - Board 175

Over the past decades, reliable algorithms have been developed for retrieving cloud properties, radiative fluxes and the resulting cloud radiative effects from multispectral satellite images. These products are nowadays used in applications ranging from climate and weather research to nowcasting of energy production by solar power plants. The accuracy of retrieved solar surface irradiance is commonly assessed using high-quality ground-based observations as reference. Due to the high variability of clouds and the solar radiation, large deviations occur frequently on an instantaneous basis. Thus, sufficiently long periods are commonly used for validation studies in order to quantify random and systematic uncertainties. This averaging however also restricts our ability to test radiative closure on a case-by-case basis. Several physical mechanisms limit the instantaneous correspondence of ground-based and satellite observations, and thus contribute to the total deviation: while satellite products correspond to a spatial area given by the pixel resolution, ground-based observations are point measurements with limited representativeness for extended spatial domains. The effects of 3D radiative transfer and horizontal photon transport cause a decorrelation of the solar irradiance at the top and bottom of the atmosphere. In addition, cloud variability and thus the uncertainty depends strongly on cloud type and synoptic conditions. A better understanding of these effects is highly desirable to advance our understanding of cloud-radiation interactions and to assess radiative closure in cloudy conditions. In the present study, solar surface irradiance as retrieved from METEOSAT SEVIRI‘s rapid scan service with a 5-minute repeat cylce are compared to a unique dataset of spatially resolved solar surface irradiance measured by a dense network of 99 autonomous pyranometers, which was operated across a 10x10km² domain during the HOPE field campaing from April-July 2013 in Western Germany. A novel cloud and irradiance retrieval utilizing SEVIRI‘s high-resolution visible channel at a 1x1km² nadir pixel resolution is contrasted to the standard resolution products at 3x3km² to study the influence of sensor resolution on the accuracy of satellite retrievals versus individual stations. Using the optimum averaging technique and the dense coverage of pyranometer observations, this accuracy is contrasted to that obtained against estimates of the spatial average for both pixel resolutions, demonstrating a significantly higher remaining uncertainty for the higher spatial resolution, likely attributable to 3D radiative effects. A cloud-type classification is applied to group uncertainties according to synoptic conditions, and a wavelet-based multi-resolution analysis is used to compare the power spectra of both datasets, to establish their correlation, and to quantify the effects of spatial and temporal averaging. Finally, conclusions are drawn for the for the feasibility of a field campaign for testing radiative closure at the surface for the EarthCARE satellite mission, and for the expected increases in accuracy for products from the upcoming Meteosat Third Generation Flexible Combined Imager.

Area B - Board 176

Understanding the role of cloud radiative effects in the Earth’s climate system is of fundamental importance for improving our knowledge about cloud feedbacks in a changing climate. Besides atmospheric models, global observations are needed to study the impact of clouds on the radiation depending on the clouds’ properties. This requires reliable data of both cloud properties and radiative fluxes at the top of the atmosphere and at the surface, ideally collocated at the spatial scales of clouds.

Recently, the ESA Cloud_cci project generated v3.0 of a multi-decadal cloud property and radiative flux dataset based on the polar-orbiting, passive imaging AVHRR sensor. This new version is characterized by increased quality compared to earlier versions and extended temporal coverage (1982-2016). In a first retrieval step the cloud properties are derived, which are then further utilized in the calculation of the radiative fluxes (at the surface and at top of the atmosphere), which additionally required reanalysis information. Through this approach, the presented dataset is excellently suited for in-depth studies of the impact of clouds on the Earth’s radiation budget. Through its length, the Cloud_cci AVHRR-PMv3 additionally supports studies on the response of clouds and their radiative effect to less frequent phenomena such as strong El Niño events as well as on the general response of clouds and their radiative effect to a changing climate.

In the presentation we will motivate the importance of this topic and motivate the need for this new observational dataset to achieve advanced insights. After demonstrating the good agreement of the AVHRR-PMv3 dataset’s cloud and radiative properties (e.g. to CERES and BSRN), the main focus of the presentation will be on using the new dataset for quantifying the cloud radiative effect, as important component in the Earth’s radiation budget, and describing the dependence of that on multiple cloud properties. We will also give an outlook on how the new data can and will be used for assessing cloud radiative feedbacks depending on cloud properties, frequencies and region.

Area B - Board 177

This study highlights the sensitivity of top-of-atmosphere shortwave (TOA SW) anisotropy – essential to convert satellite-based instantaneous TOA SW radiance measurements into TOA SW fluxes – to cloud-top effective radii and cloud-topped water vapor. We used several years of CERES (Clouds and the Earth's Radiant Energy System) SSF (Single Scanner Footprint ) observations and filtered for footprints containing horizontally homogeneous and fully overcast low-level clouds of optical thickness 10. To complement observations we simulated azimuthally resolved broadband radiances over sub-adiabatic clouds using MOMO (Matrix Operator Model, Hollstein and Fischer, 2012, DOI: 10.1016/j.jqsrt.2012.01.010). Cloud properties, retrieved from MODIS (Moderate-resolution Imaging Spectroradiometer) observations, paired with meteorological data from GEOS (Goddard Earth Observing System ) allowed to infer on each footprint’s column amount of water vapor above cloud-top, referred to as cloud-topped water vapor (CTWV). Incorporating CTWV and MODIS cloud-top effective radius, we build refined empirical Angular Distribution Models (ADMs). The ADMs showed anisotropy fluctuations particularly around the cloud bow and cloud glory (up to 2.9–8.0%) for various effective radii and at highest and lowest viewing zenith angles under varying amounts of cloud-topped moisture (up to 1.3–6.4%). As a consequence, flux estimates from refined ADMs differed from CERES estimates by up to 20 W/m² at particular combinations of viewing and illumination geometry. When applied to CERES cross-track observation of January and July 2007 – entering global radiation budget climatologies for benchmark comparisons with global climate models - we found that such differences between refined and CERES ADMs introduced large-scale biases of 1–2 W/m² and on regional levels of up to 10 W/m². These biases could be attributed in part to low cloud-top effective radii (about 8 μm) and low cloud-topped water vapor (1.7 kg/m²) and in part to an inopportune correlation of viewing and illumination conditions with temporally varying effective radii and cloud-topped moisture, which failed to compensate towards vanishing flux bias. This study may help avoid sampling biases due to discrepancies between individual samples and the median cloud-top effective radii and cloud-top moisture conditions represented in current ADMs.

Area B - Board 178

Cumulating ocean-atmospheric thermal energy caused by global warming has resulted in the reversal of the energy balance towards the poles. This situation is characterized by a new ocean-continental thermal distribution: over the ocean, the balance is more in excess than in the mainland, if not the opposite when the balance is negative inland.
Thanks to satellite observation and daily monitoring of meteorological conditions for more than ten years, we have observed that the positive balance has shifted more towards the poles, mainly in the northern hemisphere. Subtropical anticyclones are strengthened and have extended to high latitudes, especially over the Atlantic and Pacific oceans. This situation creates global peaks strengthened in winter periods, and imposes on cosmic cold the deep advection toward the south under the form of planetary valleys "Polar Vortex".
This situation imposes on the jet stream a pronounced ripple and installs a meridional atmospheric circulation (MAC) in winter, which brings the warm tropical air masses to reach the Arctic Circle, and cold polar air masses to reach North Africa and Florida.
This situation creates unusual atmospheric events, characterized by hydrothermal "extreme" conditions: excessive heat at high latitudes, accompanied by heavy rains and floods, as well as cold at low latitudes and the appearance of snow in the Sahara!
The populations are profoundly influenced by the new phenomena. The socioeconomic infrastructures can no longer assume their basic functions and man when unprotected is weak and hence the advanced vulnerability of all the regions especially those belonging to poor and developing countries
This is why climate sciences must deal nowadays with short term prediction of phenomena: weekly, monthly, or seasonly a bit more advanced than meteorology (72 hours) but less advanced than climate models (50-100 years) to allow the policy makers enough time to intervene efficiently in order to protect the populations from extreme meteorological phenomena and to benefit from the opportunities of the new meteorological conditions
These are the characteristics of "New Meteorological Events" resulting from the "New Atmospheric Circulation", caused by the "New planetary Climate" consequence of "Global Warming".
It is the new global challenge.

Area B - Board 179

Atmospheric remote sounding sounding from satellites is an essential component of the observational strategy deployed to monitor climate change. The Infrared Atmospheric Sounding Interferometer (IASI) is a nadir looking thermal infrared spectrometer flying on board the satellites Metop-A, Metop-B and Metop-C, launched in 2006, 2012 and 2018 respectively. Each IASI observation measures Earth’s infrared radiance over 8461 channels between 645 and 2760 cm-1. Every location on Earth is observed twice a day by IASI, in the morning and in the evening, which gives us good spatial and temporal coverage. Atmospheric temperatures at different altitudes can be retrieved from the radiances measured in the carbon dioxide absorption bands at 15 μm (645 to 800 cm-1) and 4.3 μm (2250 to 2400 cm-1) by selecting channels that are most sensitive to the temperature profile. The European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) already calculates atmospheric temperatures from IASI and other instruments on board of the Metop satellites. Several updates of their retrieval algorithm have had a significant effect on the atmospheric temperatures, and the whole time series has not been reprocessed back in time and therefore no homogeneous record of atmospheric temperatures exists.

In this talk, we perform our own selection of IASI channels relevant for temperature retrievals. By carefully selecting radiances, a method is then applied to the full IASI time series and trend analysis is performed. The IASI temperatures are compared to temperatures from ERA5 reanalysis to determine their quality at different atltitudes and latitudes.

This project brings continuous and independent information on atmospheric temperature which will allow us to study seasonal and spatial variability of temperature. It will also be possible to analyze the influence of natural events such as El Niño - Southern Oscillation (ENSO) on atmospheric temperature, and deduce climate change signature.

Area B - Board 180

The Climate Monitoring SAF aims at providing high quality Climate Data Records, based on data from weather satellites. The product's portfolio mostly relates to the energy flow in the climate system with variables like: the top-of-atmosphere radiation, the surface radiation and albedo, and the clouds properties. The water cycle is also addressed with the HOAPS retrieval (ocean only) and will be extended during CDOP-3 with global precipitation and land surface turbulent fluxes products. Still, an important climate variable is missing for a complete description of the energy and water cycle: the aerosol optical depth (AOD) which has a known effect on the climate through scattering and absorption of radiation. A good illustration of this is the negative forcing ("cooling") that followed the eruption of the Mount Pinatubo.
Although the current instruments on geostationary satellites were not designed for aerosol observations, their high temporal and spatial sampling has proven to be useful by providing more frequent observations of cloud free conditions than dedicated instruments on polar satellites. The use of the diurnal cycle also permits an objective separation of the surface and aerosol signals that results in consistent surface albedo and aerosol optical depth products. The aerosol signal is high for the low sun conditions near sunrise and sunset. This approach has been implemented in different algorithms like the Geostationary Surface Albedo (GSA), the Land Daily Aerosol (LDA) and the Aerosol and surface albEdo Retrieval Using a directional Splitting method-application to GEOstationary data (AERUS-GEO).
Recently, the LDA algorithm was applied to MSG/SEVIRI to generate an "interim" Climate Data Record of AOD covering 2004-2012. The data record, now available via the CM SAF at http://www.cmsaf.eu, includes the daily mean and monthly mean AOD at the full SEVIRI resolution (3 km at nadir). Extensive validations have been performed, primarily using the AeroNet observations but also by intercomparison with other satellite remote sensing products like MODIS and AERUS-GEO. The strengths and limitations of the data record, in the context of climate monitoring, are presented and discussed.
Finally, we show how this AOD record can be combined with TOA radiation data from the Geostationary Earth Radiation Budget (GERB) instruments to quantify the direct radiative effect of aerosol.

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At the European Centre for Medium-Range Weather Forecasts (ECMWF), reanalysis is a key contribution to the Copernicus Climate Service (C3S) that is implemented at ECMWF on behalf of the European Commission.

The role of reanalyses in climate monitoring applications is now widely recognized. ECMWF’s reanalysis ERA-interim is periodically used, together with other datasets, as input to the World Meteorological Organization
(WMO) annual assessment of the State of the Climate, routinely presented at the Conference of the Parties of the United Nations Framework Convention on Climate Change (UNFCCC). ERA-interim is also a resource for the production of Essential Climate Variables (ECVs) and Climate Indicators recommended by the Global Climate Observing System (GCOS). By optimally combining observations and models, reanalyses indeed provide consistent "maps without gaps" of ECVs and strive to ensure integrity and coherence in the representation of the main Earth system cycles (e.g. water, energy).

At ECMWF climate reanalysis is extended close to real time, with allows for an accurate and up-to-date monitoring. As such, C3S provides monthly-updated climate bulletin (https://climate.copernicus.eu/climate-bulletins), incorporating a global and European monitoring report covering surface air temperature, sea-ice and hydrological climate variables. These summaries are published within one week of the end of the month.

This presentation focuses on the new ECMWF atmospheric reanalysis ERA5, which (from early 2019) is publicly available from 1979 via the C3S Climate Data Store. It will soon replace the widely used ERA-Interim reanalysis. ERA5 is the fifth generation of ECMWF atmospheric reanalyses of the global climate, which was pioneered with the FGGE reanalyses produced in the 1980s, followed by ERA-15, ERA-40 and most recently ERA-Interim.

Timely updates are provided and consolidated in an official release about two months behind real time, while preliminary updates (from early 2019) are available with a latency of 2-5 days. A second phase of ERA5, a pre-extension back to 1950, is currently in production and is to be available by the fall of 2019.

ERA5 is based on a recent ECMWF model cycle which uses the 4D-Var assimilation method for the atmosphere, and includes coupling with ocean waves and a land model. Vast numbers of observations are assimilated, both in situ and from satellites, that, jointly, are sensitive to a wide range of geophysical quantities throughout the atmosphere.
In addition, a number of reprocessed data records are ingested as well as several data sets that have never been re-used before, and ERA5 is able to assimilate the latest instruments. Bias correction schemes have been extended and improved.

In contrast to ERA-Interim, radiative forcing of ERA5 follows the evolution of greenhouse gases, volcanic eruptions, ozone and aerosols as recommended by CMIP5. In addition, a consistent reconstruction is used for sea-surface temperature and sea ice.

ERA5 is produced at considerably higher resolution than ERA-Interim: hourly analysis fields are available at a horizontal resolution of 31 km on 137 levels in the vertical. ERA5 data products also include information about uncertainties which is provided by a lower-resolution 10-member 4D-Var ensemble.

These improvements provide ERA5 with a more refined and accurate evolution of global energy budgets and temperature trends.
Examples will be presented.

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In recent decades climate variability and change have caused impacts on natural and human systems on all continents. Observations are needed to understand and document these interactions. These observations are increasingly based on remote sensing from satellites which offer global scale and continuous coverage. Only long term and consistent observations of the Earth system allow us to quantify impacts of climate variability and change on the natural and human dimension. From this understanding one can estimate and eventually predict future states of the Earth system and quantify its vulnerability and resilience to continuing anthropogenic forcing.
Since nearly 20 years, the EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF, www.cmsaf.eu) develops capabilities for a sustained generation and provision of Climate Data Records (CDRs) derived from operational meteorological satellites. The ultimate aim is to make the resulting data records suitable for the analysis of climate variability and the detection of climate trends. The product portfolio of the CM SAF comprises long time series of Essential Climate Variables (ECVs) related to the energy & water cycle as defined by Global Climate Observing System (GCOS).
Several data records have been released to the public by CM SAF and new editions of CDR will be published in the coming years which will extend the time-range and the portfolio. In particular, new products related to the following topics are currently developed and provided in near future: global precipitation (ocean and land), regional land fluxes (Meteosat domain), and global high clouds. All products are well-documented, carefully validated and were externally reviewed prior to product release.
This presentation will highlight results from the currently available CDRs. A focus will be on uncertainty characterisation and on results from validation as well as exemplary applications. Finally, the presentation will present an overview of the upcoming new editions of CDRs.

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