Nitrous Oxide Profiling from Infrared Radiances (NOPIR): Algorithm Description, Application to 10 Years of IASI Observations and Quality Assessment

Author(s):
Vandenbussche, Sophie; Langerock, Bavo; Vigouroux, Corinne; Buschmann, Matthias; Deutscher, Nicholas M.; Feist, Dietrich G.; García, Omaira; Hannigan, James W.; Hase, Frank; Kivi, Rigel; Kumps, Nicolas; Makarova, Maria; Millet, Dylan B.; Morino, Isamu; Nagahama, Tomoo; Notholt, Justus; Ohyama, Hirofumi; Ortega, Ivan; Petri, Christof; Rettinger, Markus; Schneider, Matthias; Servais, Christian P.; Sha, Mahesh Kumar; Shiomi, Kei; Smale, Dan; Strong, Kimberly; Sussmann, Ralf; Té, Yao; Velazco, Voltaire A.; Vrekoussis, Mihalis; Warneke, Thorsten; Wells, Kelley C.; Wunch, Debra; Zhou, Minqiang; De Mazière, Martine
Publication title: Remote Sensing
2022
 | Volume: 14 | Issue: 8
2022
DOI: 10.3390/rs14081810
Abstract:
Nitrous oxide (N2 O) is the third most abundant anthropogenous greenhouse gas (after carbon dioxide and methane), with a long atmospheric lifetime and… Nitrous oxide (N2 O) is the third most abundant anthropogenous greenhouse gas (after carbon dioxide and methane), with a long atmospheric lifetime and a continuously increasing concentration due to human activities, making it an important gas to monitor. In this work, we present a new method to retrieve N2 O concentration profiles (with up to two degrees of freedom) from each cloud-free satellite observation by the Infrared Atmospheric Sounding Interferometer (IASI), using spectral micro-windows in the N2 O ν3 band, the Radiative Transfer for TOVS (RTTOV) tools and the Tikhonov regularization scheme. A time series of ten years (2011–2020) of IASI N2 O profiles and integrated partial columns has been produced and validated with collocated ground-based Network for the Detection of Atmospheric Composition Change (NDACC) and Total Carbon Column Observing Network (TCCON) data. The importance of consistency in the ancillary data used for the retrieval for generating consistent time series has been demonstrated. The Nitrous Oxide Profiling from Infrared Radiances (NOPIR) N2 O partial columns are of very good quality, with a positive bias of 1.8 to 4% with respect to the ground-based data, which is less than the sum of uncertainties of the compared values. At high latitudes, the comparisons are a bit worse, due to either a known bias in the ground-based data, or to a higher uncertainty in both ground-based and satellite retrievals. © 2022 by the authors. Licensee MDPI, Basel, Switzerland. more
Application Atmosphere NWP-SAF Software for CDR development

NWCSAF AVHRR Cloud Detection and Analysis Using Dynamic Thresholds and Radiative Transfer Modeling. Part I: Algorithm Description

Author(s):
Dybbroe, Adam; Karlsson, Karl-Göran; Thoss, Anke
Publication title: Journal of Applied Meteorology
2005
 | Volume: 44 | Issue: 1
2005
DOI: 10.1175/JAM-2188.1
Abstract:
Abstract New methods and software for cloud detection and classification at high and midlatitudes using Advanced Very High Resolution Radi… Abstract New methods and software for cloud detection and classification at high and midlatitudes using Advanced Very High Resolution Radiometer (AVHRR) data are developed for use in a wide range of meteorological, climatological, land surface, and oceanic applications within the Satellite Application Facilities (SAFs) of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), including the SAF for Nowcasting and Very Short Range Forecasting Applications (NWCSAF) project. The cloud mask employs smoothly varying (dynamic) thresholds that separate fully cloudy or cloud-contaminated fields of view from cloud-free conditions. Thresholds are adapted to the actual state of the atmosphere and surface and the sun–satellite viewing geometry using cloud-free radiative transfer model simulations. Both the cloud masking and the cloud-type classification are done using sequences of grouped threshold tests that employ both spectral and textural features. The cloud-type classification divides the cloudy pixels into 10 different categories: 5 opaque cloud types, 4 semitransparent clouds, and 1 subpixel cloud category. The threshold method is fuzzy in the sense that the distances in feature space to the thresholds are stored and are used to determine whether to stop or to continue testing. They are also used as a quality indicator of the final output. The atmospheric state should preferably be taken from a short-range NWP model, but the algorithms can also run with climatological fields as input. more
Atmosphere Method NWC-SAF Software for CDR development Validation

NWCSAF High Resolution Winds (NWC/GEO-HRW) Stand-Alone Software for Calculation of Atmospheric Motion Vectors and Trajectories

Author(s):
García-Pereda, Javier; Fernández-Serdán, José; Alonso, Óscar; Sanz, Adrián; Guerra, Rocío; Ariza, Cristina; Santos, Inés; Fernández, Laura
Publication title: Remote Sensing
2019
 | Volume: 11 | Issue: 17
2019
DOI: 10.3390/rs11172032
Abstract:
The High Resolution Winds (NWC/GEO-HRW) software is developed by the EUMETSAT Satellite Application Facility on Support to Nowcasting and Very Short R… The High Resolution Winds (NWC/GEO-HRW) software is developed by the EUMETSAT Satellite Application Facility on Support to Nowcasting and Very Short Range Forecasting (NWCSAF). It is part of a stand-alone software package for the calculation of meteorological products with geostationary satellite data (NWC/GEO). NWCSAF High Resolution Winds provides a detailed calculation of Atmospheric Motion Vectors (AMVs) and Trajectories, locally and in near real time, using as input geostationary satellite image data, NWP model data, and OSTIA sea surface temperature data. The whole NWC/GEO software package can be obtained after registration at the NWCSAF Helpdesk, www.nwcsaf.org, where users also find support and help for its use. NWC/GEO v2018.1 software version, available since autumn 2019, is able to process MSG, Himawari-8/9, GOES-N, and GOES-R satellite series images, so that AMVs and trajectories can be calculated all throughout the planet Earth with the same algorithm and quality. Considering other equivalent meteorological products, in the ‘2014 and 2018 AMV Intercomparison Studies’ NWCSAF High Resolution Winds compared very positively with six other AMV algorithms for both MSG and Himawari-8/9 satellites. Finally, the Coordination Group for Meteorological Satellites (CGMS) recognized in its ‘2012 Meeting Report’: (1) NWCSAF High Resolution Winds fulfills the requirements to be a portable stand-alone AMV calculation software due to its easy installation and usability. (2) It has been successfully adopted by some CGMS members and serves as an important tool for development. It is modular, well documented, and well suited as stand-alone AMV software. (3) Although alternatives exist as portable stand-alone AMV calculation software, they are not as advanced in terms of documentation and do not have an existing Helpdesk. more
Atmosphere Method NWC-SAF Software for CDR development

Observationally-constrained projections of an ice-free Arctic even under a low emission scenario

Author(s):
Kim, Yeon-Hee; Min, Seung-Ki; Gillett, Nathan P.; Notz, Dirk; Malinina, Elizaveta
Publication title: Nature Communications
2023
 | Volume: 14 | Issue: 1
2023
DOI: 10.1038/s41467-023-38511-8
Abstract:
The sixth assessment report of the IPCC assessed that the Arctic is projected to be on average practically ice-free in September near mid-century unde… The sixth assessment report of the IPCC assessed that the Arctic is projected to be on average practically ice-free in September near mid-century under intermediate and high greenhouse gas emissions scenarios, though not under low emissions scenarios, based on simulations from the latest generation Coupled Model Intercomparison Project Phase 6 (CMIP6) models. Here we show, using an attribution analysis approach, that a dominant influence of greenhouse gas increases on Arctic sea ice area is detectable in three observational datasets in all months of the year, but is on average underestimated by CMIP6 models. By scaling models’ sea ice response to greenhouse gases to best match the observed trend in an approach validated in an imperfect model test, we project an ice-free Arctic in September under all scenarios considered. These results emphasize the profound impacts of greenhouse gas emissions on the Arctic, and demonstrate the importance of planning for and adapting to a seasonally ice-free Arctic in the near future. more
Climate Data Records Cryosphere OSI-SAF Ocean Validation

Observations for Model Intercomparison Project (Obs4MIPs): status for CMIP6

Author(s):
Waliser, Duane; Gleckler, Peter J.; Ferraro, Robert; Taylor, Karl E.; Ames, Sasha; Biard, James; Bosilovich, Michael G.; Brown, Otis; Chepfer, Helene; Cinquini, Luca; Durack, Paul J.; Eyring, Veronika; Mathieu, Pierre-Philippe; Lee, Tsengdar; Pinnock, Simon; Potter, Gerald L.; Rixen, Michel; Saunders, Roger; Schulz, Jörg; Thépaut, Jean-Noël; Tuma, Matthias
Publication title: Geoscientific Model Development
2020
 | Volume: 13 | Issue: 7
2020
DOI: 10.5194/gmd-13-2945-2020
Abstract:
Abstract. The Observations for Model Intercomparison Project (Obs4MIPs) was initiated in 2010 to facilitate the use of observations in climate model e… Abstract. The Observations for Model Intercomparison Project (Obs4MIPs) was initiated in 2010 to facilitate the use of observations in climate model evaluation and research, with a particular target being the Coupled Model Intercomparison Project (CMIP), a major initiative of the World Climate Research Programme (WCRP). To this end, Obs4MIPs (1) targets observed variables that can be compared to CMIP model variables; (2) utilizes dataset formatting specifications and metadata requirements closely aligned with CMIP model output; (3) provides brief technical documentation for each dataset, designed for nonexperts and tailored towards relevance for model evaluation, including information on uncertainty, dataset merits, and limitations; and (4) disseminates the data through the Earth System Grid Federation (ESGF) platforms, making the observations searchable and accessible via the same portals as the model output. Taken together, these characteristics of the organization and structure of obs4MIPs should entice a more diverse community of researchers to engage in the comparison of model output with observations and to contribute to a more comprehensive evaluation of the climate models. At present, the number of obs4MIPs datasets has grown to about 80; many are undergoing updates, with another 20 or so in preparation, and more than 100 are proposed and under consideration. A partial list of current global satellite-based datasets includes humidity and temperature profiles; a wide range of cloud and aerosol observations; ocean surface wind, temperature, height, and sea ice fraction; surface and top-of-atmosphere longwave and shortwave radiation; and ozone (O3), methane (CH4), and carbon dioxide (CO2) products. A partial list of proposed products expected to be useful in analyzing CMIP6 results includes the following: alternative products for the above quantities, additional products for ocean surface flux and chlorophyll products, a number of vegetation products (e.g., FAPAR, LAI, burned area fraction), ice sheet mass and height, carbon monoxide (CO), and nitrogen dioxide (NO2). While most existing obs4MIPs datasets consist of monthly-mean gridded data over the global domain, products with higher time resolution (e.g., daily) and/or regional products are now receiving more attention. Along with an increasing number of datasets, obs4MIPs has implemented a number of capability upgrades including (1) an updated obs4MIPs data specifications document that provides additional search facets and generally improves congruence with CMIP6 specifications for model datasets, (2) a set of six easily understood indicators that help guide users as to a dataset's maturity and suitability for application, and (3) an option to supply supplemental information about a dataset beyond what can be found in the standard metadata. With the maturation of the obs4MIPs framework, the dataset inclusion process, and the dataset formatting guidelines and resources, the scope of the observations being considered is expected to grow to include gridded in situ datasets as well as datasets with a regional focus, and the ultimate intent is to judiciously expand this scope to any observation dataset that has applicability for evaluation of the types of Earth system models used in CMIP. more
Atmosphere Cryosphere EUM-Secr International cooperation Land Method Ocean

Observed Landscape Responsiveness to Climate Forcing

Author(s):
Feldman, Andrew F.; Short Gianotti, Daniel J.; Trigo, Isabel F.; Salvucci, Guido D.; Entekhabi, Dara
Publication title: Water Resources Research
2022
 | Volume: 58 | Issue: 1
2022
DOI: 10.1029/2021WR030316
Abstract:
Climate variability and change shift environmental conditions on global land surfaces, creating uncertainties in predicting hydrologic flows, crop yie… Climate variability and change shift environmental conditions on global land surfaces, creating uncertainties in predicting hydrologic flows, crop yields, and land carbon uptake. Land surfaces can present varying degrees of inertia to atmospheric forcing variability (e.g., precipitation). This study asks: are regions with the most variable environmental forcing necessarily the regions with the largest land surface variability? Specifically, it seeks to determine why land surfaces show varying responsiveness to environmental forcing. The degree to which and the mechanisms for how landscapes modulate the forcing are evaluated using a decade-long satellite observation record of Africa's diverse climates. Surface responsiveness is quantified using intra-seasonal energy flux variability, based on the observed diurnal temperature amplitude. We map the responsiveness and analyze the underlying mechanisms over intra-seasonal timescales (especially interstorms). We show that, at a location, land surface responsiveness is dependent on the soil moisture distribution and the nonlinear relationship between energy fluxes and soil moisture. Land surfaces with greater responsiveness to climate are those with soil moisture distributions that span the threshold between evaporation regimes and spend most of their time in the water-limited regime. Consequently, surface responsiveness mechanisms drive land surface variability beyond high climatic variability. Since we find these results to hold from intra-seasonal to interannual timescales, we expect that these responsive regions will be most vulnerable to long-term shifts in climate forcing. The quantification of these phenomena and determination of their geographic distributions based on observations can help assess land surface models used to evaluate hydrologic consequences of climate change. more
Application Climate Data Records LSA-SAF Land

Observations and Implications of Diurnal Climatology and Trends in Direct and Diffuse Solar Radiation Over China

Author(s):
Wang, Y.; Zhang, J.; Trentmann, J.; Fiedler, S.; Yang, S.; Sanchez-Lorenzo, A.; Tanaka, K.; Yuan, W.; Wild, M.
Publication title: Journal of Geophysical Research: Atmospheres
2022
 | Volume: 127 | Issue: 15
2022
DOI: 10.1029/2022JD036769
Abstract:
Solar radiation received at the Earth's surface (Rs) is comprised of two components, the direct radiation (Rd) and the diffuse radiation (Rf). Rd, the… Solar radiation received at the Earth's surface (Rs) is comprised of two components, the direct radiation (Rd) and the diffuse radiation (Rf). Rd, the direct beam from the sun, is essential for concentrated solar power generation. Rf, scattered by atmospheric molecules, aerosols, or cloud droplets, has a fertilization effect on plant photosynthesis. But how Rd and Rf change diurnally is largely unknown owing to the lack of long-term measurements. Taking advantage of 22 years of homogeneous hourly surface observations over China, this study documents the climatological means and evolutions in the diurnal cycles of Rd and Rf since 1993, with an emphasis on their implications for solar power and agricultural production. Over the solar energy resource region, we observe a loss of Rd which is relatively large near sunrise and sunset at low solar elevation angles when the sunrays pass through the atmosphere on a longer pathway. However, the concentrated Rd energy covering an average 10-hr period around noon during a day is relatively unaffected. Over the agricultural crop resource region, the large amounts of clouds and aerosols scattering more of the incoming light result in Rf taking the main proportion of Rs during the whole day. Rf resources and their fertilization effect in the main crop region of China further enhances since 1993 over almost all hours of the day. © 2022. American Geophysical Union. All Rights Reserved. more
Application Atmosphere CM-SAF Climate Data Records

Observations for Reanalyses

Author(s):
Brönnimann, Stefan; Allan, Rob; Atkinson, Christopher; Buizza, Roberto; Bulygina, Olga; Dahlgren, Per; Dee, Dick; Dunn, Robert; Gomes, Pedro; John, Viju O.; Jourdain, Sylvie; Haimberger, Leopold; Hersbach, Hans; Kennedy, John; Poli, Paul; Pulliainen, Jouni; Rayner, Nick; Saunders, Roger; Schulz, Jörg; Sterin, Alexander; Stickler, Alexander; Titchner, Holly; Valente, Maria Antonia; Ventura, Clara; Wilkinson, Clive
Publication title: Bulletin of the American Meteorological Society
2018
 | Volume: 99 | Issue: 9
2018
DOI: 10.1175/BAMS-D-17-0229.1
Abstract:
Abstract Global dynamical reanalyses of the atmosphere and ocean fundamentally rely on observations, not just for the assimilation (i.e., for the defi… Abstract Global dynamical reanalyses of the atmosphere and ocean fundamentally rely on observations, not just for the assimilation (i.e., for the definition of the state of the Earth system components) but also in many other steps along the production chain. Observations are used to constrain the model boundary conditions, for the calibration or uncertainty determination of other observations, and for the evaluation of data products. This requires major efforts, including data rescue (for historical observations), data management (including metadatabases), compilation and quality control, and error estimation. The work on observations ideally occurs one cycle ahead of the generation cycle of reanalyses, allowing the reanalyses to make full use of it. In this paper we describe the activities within ERA-CLIM2, which range from surface, upper-air, and Southern Ocean data rescue to satellite data recalibration and from the generation of snow-cover products to the development of a global station data metadatabase. The project has not produced new data collections. Rather, the data generated has fed into global repositories and will serve future reanalysis projects. The continuation of this effort is first contingent upon the organization of data rescue and also upon a series of targeted research activities to address newly identified in situ and satellite records. more
Application EUM-Secr International cooperation Validation

Observed and CMIP5-Simulated Radiative Flux Variability Over West Africa

Author(s):
Mackie, A.; Wild, M.; Brindley, H.; Folini, D.; Palmer, P.I.
Publication title: Earth and Space Science
2020
 | Volume: 7 | Issue: 5
2020
DOI: 10.1029/2019EA001017
Abstract:
We explore the ability of general circulation models in the Coupled Model Intercomparison Project (CMIP5) to recreate observed seasonal variability in… We explore the ability of general circulation models in the Coupled Model Intercomparison Project (CMIP5) to recreate observed seasonal variability in top-of-the-atmosphere and surface radiation fluxes over West Africa. This tests CMIP5 models' ability to describe the radiative energy partitioning, which is fundamental to our understanding of the current climate and its future changes. We use 15 years of the monthly Clouds and the Earth's Radiant Energy System Energy Balanced and Filled (EBAF) product, alongside other satellite, reanalysis, and surface station products. We find that the CMIP5 multimodel mean is generally within the reference product range, with annual mean CMIP5 multimodel mean—EBAF of −0.5 W m−2 for top-of-the-atmosphere reflected shortwave radiation, and 4.6 W m−2 in outgoing longwave radiation over West Africa. However, the range in annual mean of the model seasonal cycles is large (37.2 and 34.0 W m−2 for reflected shortwave radiation and outgoing longwave radiation, respectively). We use seasonal and regional contrasts in all-sky fluxes to infer that the representation of the West African monsoon in numerical models affects radiative energy partitioning. Using clear-sky surface fluxes, we find that the models tend to have more downwelling shortwave and less downwelling longwave radiation than EBAF, consistent with past research. We find models that are drier and have lower aerosol loading tend to show the largest differences. We find evidence that aerosol variability has a larger effect in modulating downwelling shortwave radiation than water vapor in EBAF, while the opposite effect is seen in the majority of CMIP5 models. ©2020. The Authors. more
Application Atmosphere CM-SAF Climate Data Records

Observed Temperature Changes in the Troposphere and Stratosphere from 1979 to 2018

Author(s):
Steiner, A. K.; Ladstädter, F.; Randel, W. J.; Maycock, A. C.; Fu, Q.; Claud, C.; Gleisner, H.; Haimberger, L.; Ho, S.-P.; Keckhut, P.; Leblanc, T.; Mears, C.; Polvani, L. M.; Santer, B. D.; Schmidt, T.; Sofieva, V.; Wing, R.; Zou, C.-Z.
Publication title: Journal of Climate
2020
 | Volume: 33 | Issue: 19
2020
DOI: 10.1175/JCLI-D-19-0998.1
Abstract:
Abstract Temperature observations of the upper-air atmosphere are now available for more than 40 years from both ground- and satellite-bas… Abstract Temperature observations of the upper-air atmosphere are now available for more than 40 years from both ground- and satellite-based observing systems. Recent years have seen substantial improvements in reducing long-standing discrepancies among datasets through major reprocessing efforts. The advent of radio occultation (RO) observations in 2001 has led to further improvements in vertically resolved temperature measurements, enabling a detailed analysis of upper-troposphere/lower-stratosphere trends. This paper presents the current state of atmospheric temperature trends from the latest available observational records. We analyze observations from merged operational satellite measurements, radiosondes, lidars, and RO, spanning a vertical range from the lower troposphere to the upper stratosphere. The focus is on assessing climate trends and on identifying the degree of consistency among the observational systems. The results show a robust cooling of the stratosphere of about 1–3 K, and a robust warming of the troposphere of about 0.6–0.8 K over the last four decades (1979–2018). Consistent results are found between the satellite-based layer-average temperatures and vertically resolved radiosonde records. The overall latitude–altitude trend patterns are consistent between RO and radiosonde records. Significant warming of the troposphere is evident in the RO measurements available after 2001, with trends of 0.25–0.35 K per decade. Amplified warming in the tropical upper-troposphere compared to surface trends for 2002–18 is found based on RO and radiosonde records, in approximate agreement with moist adiabatic lapse rate theory. The consistency of trend results from the latest upper-air datasets will help to improve understanding of climate changes and their drivers. more
Application Atmosphere Climate Data Records ROM-SAF
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