Validation of downward surface radiation derived from MSG data by in-situ observations over the Atlantic ocean

The present work investigates the quality of the shortwave and and longwave downward radiation (DSR, DLR) at the sea surface over the Atlantic Ocean as retrieved from Meteosat Second Generation (MSG) measurements and EUMETSAT's Climate Monitoring - Satellite Application Facility (CM-SAF) algorithms. The observations taken at two transatlantic research cruises have been an ideal basis to be compared with the MSG products for DSR and DLR derived from Meteosat-8 and Meteosat-9. Onboard the research vessels "Akademik Ioffe" and "Polarstern" high quality in situ measurements of both radiation fluxes have been performed. Continuous full sky imagery and standard meteorological observations enable a comprehensive evaluation of the skills of MSG DSR- and DLR-retrievals in different climate zones and under various cloud and weather conditions. The DSR was retrieved by MSG with a positive bias of 2.77 Wm−2 during the Ioffe cruise, and 22.23 Wm−2 during the Polarstern cruise. The bias for the DLR was −1.73 Wm−2 and 2.76 Wm−2, respectively. The differences between the two cruises mainly arise from the different weather conditions. No significant differences between the satellite products from Meteosat-8 and Meteosat-9 were found. In general DSR and DLR for clear sky conditions are captured with a high accuracy. Largest retrieval errors occur for fast fluctuating broken cloud conditions, though on average the MSG algorithm match the in-situ observations well. Semitransparent cirrus was found to cause a negative bias for the retrieved DSR. In tropics and subtropics the errors for DLR are smaller compared to higher latitudes. Most importantly, no significant dependencies of the satellite retrieval errors for both the DSR and the DLR on the solar elevation, near-surface humidity, cloud cover, SST and the shift of day and night were found, indicating that the CM-SAF radiation products are not subject to significant systematic errors. Diese Arbeit evaluiert die Qualität der abwärtsgerichteten kurzwelligen Einstrahlung (DSR) und der abwärtsgerichteten langwelligen Gegenstrahlung (DLR) an der Meeresoberfläche des Atlantischen Ozeans, berechnet aus Fernerkundungsdaten von Meteosat Second Generation (MSG) mit Hilfe der EUMETSAT Climate Monitoring - Satellite Application Facility (CM-SAF) - Algorithmen. Die auf zwei transatlantischen Forschungsfahrten gewonnenen Beobachtungsdaten stellen eine ideale Basis für den Vergleich mit den MSG-Produkten DSR und DLR dar, die aus Daten des Meteosat-8 und Meteosat-9 abgeleitet wurden. An Bord der Forschungsschiffe Akademik Ioffe und Polarstern wurden hochwertige in situ Messungen beider Strahlungsflüsse durchgeführt. Kontinuierliche Sequenzen der Wolkenkamera in Verbindung mit meteorologischen Standardmessungen ermöglichen diese Vergleichsstudie mit den Ergebnissen der MSG-Algorithmen für DSR und DLR in unterschiedlichen Klimazonen und unter verschiedensten Wolken- und Wetterbedingungen. Für die Fahrt der Ioffe zeigte die DSR abgeleitet aus MSG-Daten eine Überschätzung von 2.77 Wm−2, für die Fahrt der Polarstern wurden 22.23 Wm−2 ermittelt. Der systematische Fehler der DLR war −1.73 Wm−2 bzw. 2.76 Wm−2. Die unterschiedlichen Werte der beiden Fahrten resultieren hauptsächlich aus den verschiedenen Wetterbedingungen. Durch den zeitlichen Überlapp konnten Satellitenprodukte von Meteosat-8 und Meteosat-9 verglichen werden, die keine signifikanten Unterschiede zeigten. Im Allgemeinen werden DSR und DLR im wolkenfreien Fall mit hoher Genauigkeit wiedergegeben. Die größten Fehler im Algorithmus kommen bei sich schnell ändernder Cumulusbedeckung vor, wobei die berechneten Einstrahlungen im Mittel gut mit den in situ Messungen übereinstimmen. Semitransparenter Cirrus verursacht Unterschätzungen in der abgeleiteten DSR. In Tropen und Subtropen sind die Fehler in der DLR geringer als in hohen Breiten. Wichtig ist die Tatsache, dass der Fehler für den Satellitenalgorithmus sowohl für DSR als auch für DLR keine signifikanten Abhängigkeiten von dem Sonnenstand, von der Luftfeuchtigkeit in Bodennähe, vom Wolkenbedeckungsgrad, von der SST und vom Tag-Nacht-Unterschied zeigen. Dies weißt darauf hin, dass die CM-SAF Strahlungsprodukte keinen signifikanten systematischen Fehlern unterliegen

Ableitung aus Satellitendaten; Validation eines regionalen Modells

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Decomposition of Random Errors Inherent to HOAPS-3.2 Near-Surface Humidity Estimates Using Multiple Triple Collocation Analysis

Latent heat fluxes (LHF) play an essential role in the global energy budget and are thus important for understanding the climate system. Satellite-based remote sensing permits a large-scale determination of LHF, which, amongst others, are based on near-surface specific humidity qa. However, the qa random retrieval error (Etot) remains unknown. Here, a novel approach is presented to quantify the error contributions to pixel-level qa of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS, version 3.2) dataset. The methodology makes use of multiple triple collocation (MTC) analysis between 1995-2008 over the global ice-free oceans. Apart from satellite records, these datasets include selected ship records extracted from the Seewetteramt Hamburg (SWA) archive and the International Comprehensive Ocean-Atmosphere Data Set (ICOADS), serving as the in-situ ground reference. The MTC approach permits the derivation of Etot as the sum of model uncertainty EM and sensor noise EN, while random uncertainties due to in-situ measurement errors (Eins) and collocation (EC) are isolated concurrently. Results show an Etot average of 1.1 ± 0.3 g kg-1, whereas the mean EC (Eins) is in the order of 0.5 ± 0.1 g kg-1 (0.5 ± 0.3 g kg-1). Regional analyses indicate a maximum of Etot exceeding 1.5 g kg-1 within humidity regimes of 12-17 g kg-1, associated with the single-parameter, multilinear qa retrieval applied in HOAPS. Multi-dimensional bias analysis reveals that global maxima are located off the Arabian Peninsula

El balance de radiación de onda corta en superficie a partir de medidas de satélite

Ponencia presentada en: II Congreso de la Asociación Española de Climatología “El tiempo del clima”, celebrado en Valencia del 7 al 9 de junio de 2001[ES]En este trabajo se presenta un cálculo del balance de radiación solar en superficie a partir de medidas realizadas con el sensor ScaRaB (Scanner for Radiation Budget) desde marzo de 1994 hasta febrero de 1995, lo que permite obtener una climatología anual desde una perspectiva global. Se muestra de esta forma la utilidad de los sensores de banda ancha a bordo de satélites para realizar un seguimiento del balance de radiación.[EN]In this paper the surface Shortwave radiation budget computed from ScaRaB (Scanner for Radiation Budget) is obtained, from March 1994 to February 1995. This allows us to obtain an annual global climatology and shows the utility of broad-band radiometers onboard satellites to monitor the earth radiation budget

The CM SAF TOA Radiation Data Record Using MVIRI and SEVIRI

The CM SAF Top of Atmosphere (TOA) Radiation MVIRI/SEVIRI Data Record provides a homogenised satellite-based climatology of TOA Reflected Solar (TRS) and Emitted Thermal (TET) radiation in all-sky conditions over the Meteosat field of view. The continuous monitoring of these two components of the Earth Radiation Budget is of prime importance to study climate variability and change. Combining the Meteosat MVIRI and SEVIRI instruments allows an unprecedented temporal (30 min/15 min) and spatial (2.5 km/3 km) resolution compared to, e.g., the CERES products. It also opens the door to the generation of a long data record covering a 32 years time period and extending from 1 February 1983 to 30 April 2015. The retrieval method used to process the CM SAF TOA Radiation MVIRI/SEVIRI Data Record is discussed. The overlap between the MVIRI and GERB instruments in the period 2004–2006 is used to derive empirical narrowband to broadband regressions. The CERES TRMM angular dependency models and theoretical models are respectively used to compute the TRS and TET fluxes from the broadband radiances. The TOA radiation products are issued as daily means, monthly means and monthly averages of the hourly integrated values (diurnal cycle). The data is provided on a regular grid at a spatial resolution of 0.05 degrees and covers the region 70 ∘ N–70 ∘ S and 70 ∘ W–70 ∘ E. The quality of the data record has been evaluated by intercomparison with several references. In general, the stability in time of the data record is found better than 4 Wm −2 and most products fulfill the predefined accuracy requirements

Forebrain NR2B Overexpression Facilitating the Prefrontal Cortex Long-Term Potentiation and Enhancing Working Memory Function in Mice

Prefrontal cortex plays an important role in working memory, attention regulation and behavioral inhibition. Its functions are associated with NMDA receptors. However, there is little information regarding the roles of NMDA receptor NR2B subunit in prefrontal cortical synaptic plasticity and prefrontal cortex-related working memory. Whether the up-regulation of NR2B subunit influences prefrontal cortical synaptic plasticity and working memory is not yet clear. In the present study, we measured prefrontal cortical synaptic plasticity and working memory function in NR2B overexpressing transgenic mice. In vitro electrophysiological data showed that overexpression of NR2B specifically in the forebrain region resulted in enhancement of prefrontal cortical long-term potentiation (LTP) but did not alter long-term depression (LTD). The enhanced LTP was completely abolished by a NR2B subunit selective antagonist, Ro25-6981, indicating that overexpression of NR2B subunit is responsible for enhanced LTP. In addition, NR2B transgenic mice exhibited better performance in a set of working memory paradigms including delay no-match-to-place T-maze, working memory version of water maze and odor span task. Our study provides evidence that NR2B subunit of NMDA receptor in prefrontal cortex is critical for prefrontal cortex LTP and prefrontal cortex-related working memory

Plasticity in D1-Like Receptor Expression Is Associated with Different Components of Cognitive Processes

Dopamine D1-like receptors consist of D1 (D1A) and D5 (D1B) receptors and play a key role in working memory. However, their possibly differential contribution to working memory is unclear. We combined a working memory training protocol with a stepwise increase of cognitive subcomponents and real-time RT-PCR analysis of dopamine receptor expression in pigeons to identify molecular changes that accompany training of isolated cognitive subfunctions. In birds, the D1-like receptor family is extended and consists of the D1A, D1B, and D1D receptors. Our data show that D1B receptor plasticity follows a training that includes active mental maintenance of information, whereas D1A and D1D receptor plasticity in addition accompanies learning of stimulus-response associations. Plasticity of D1-like receptors plays no role for processes like response selection and stimulus discrimination. None of the tasks altered D2 receptor expression. Our study shows that different cognitive components of working memory training have distinguishable effects on D1-like receptor expression

Consistency of satellite climate data records for Earth system monitoring

Climate Data Records (CDRs) of Essential Climate Variables (ECVs) as defined by the Global Climate Observing System (GCOS) derived from satellite instruments help to characterize the main components of the Earth system, to identify the state and evolution of its processes, and to constrain the budgets of key cycles of water, carbon and energy. The Climate Change Initiative (CCI) of the European Space Agency (ESA) coordinates the derivation of CDRs for 21 GCOS ECVs. The combined use of multiple ECVs for Earth system science applications requires consistency between and across their respective CDRs. As a comprehensive definition for multi-ECV consistency is missing so far, this study proposes defining consistency on three levels: (1) consistency in format and metadata to facilitate their synergetic use (technical level); (2) consistency in assumptions and auxiliary datasets to minimize incompatibilities among datasets (retrieval level); and (3) consistency between combined or multiple CDRs within their estimated uncertainties or physical constraints (scientific level). Analysing consistency between CDRs of multiple quantities is a challenging task and requires coordination between different observational communities, which is facilitated by the CCI program. The inter-dependencies of the satellite-based CDRs derived within the CCI program are analysed to identify where consistency considerations are most important. The study also summarizes measures taken in CCI to ensure consistency on the technical level, and develops a concept for assessing consistency on the retrieval and scientific levels in the light of underlying physical knowledge. Finally, this study presents the current status of consistency between the CCI CDRs and future efforts needed to further improve it