Multiday Soil Moisture Persistence and Atmospheric Predictability Resulting From Sahelian Mesoscale Convective Systems

Author(s):
Taylor, C.M.; Klein, C.; Harris, B.L.
Publication title: Geophysical Research Letters
2024
 | Volume: 51 | Issue: 20
2024
DOI: 10.1029/2024GL109709
Abstract:
Skill in predicting where damaging convective storms will occur is limited, particularly in the tropics. In principle, near-surface soil moisture (SM)… Skill in predicting where damaging convective storms will occur is limited, particularly in the tropics. In principle, near-surface soil moisture (SM) patterns from previous storms provide an important source of skill at the mesoscale, yet these structures are often short-lived (hours to days), due to both soil drying processes and the impact of new storms. Here, we use satellite observations over the Sahel to examine how the strong, locally negative, SM-precipitation feedback there impacts rainfall patterns over subsequent days. The memory of an initial storm pattern decays rapidly over the first 3–4 days, but a weak signature is still detected in surface observations 10–20 days later. The wet soil suppresses rainfall over the storm track for the first 2–8 days, depending on aridity regime. Whilst the negative SM feedback initially enhances mesoscale rainfall predictability, the transient nature of SM likely limits forecast skill on sub-seasonal time scales. © 2024. The Author(s). more
Application Climate Data Records H-SAF Land

Network connectivity between the winter Arctic Oscillation and summer sea ice in CMIP6 models and observations

Author(s):
Gregory, William; Stroeve, Julienne; Tsamados, Michel
Publication title: CRYOSPHERE
2022
 | Volume: 16 | Issue: 5
2022
DOI: 10.5194/tc-16-1653-2022
Abstract:
The indirect effect of winter Arctic Oscillation (AO) events on the following summer Arctic sea ice extent suggests an inherent winter-to-summer mecha… The indirect effect of winter Arctic Oscillation (AO) events on the following summer Arctic sea ice extent suggests an inherent winter-to-summer mechanism for sea ice predictability. On the other hand, operational regional summer sea ice forecasts in a large number of coupled climate models show a considerable drop in predictive skill for forecasts initialised prior to the date of melt onset in spring, suggesting that some drivers of sea ice variability on longer timescales may not be well represented in these models. To this end, we introduce an unsupervised learning approach based on cluster analysis and complex networks to establish how well the latest generation of coupled climate models participating in phase 6 of the World Climate Research Programme Coupled Model Intercomparison Project (CMIP6) are able to reflect the spatio-temporal patterns of variability in Northern Hemisphere winter sea-level pressure and Arctic summer sea ice concentration over the period 1979-2020, relative to ERA5 atmospheric reanalysis and satellite-derived sea ice observations, respectively. Two specific global metrics are introduced as ways to compare patterns of variability between models and observations/reanalysis: the adjusted Rand index - a method for comparing spatial patterns of variability - and a network distance metric - a method for comparing the degree of connectivity between two geographic regions. We find that CMIP6 models generally reflect the spatial pattern of variability in the AO relatively well, although they overestimate the magnitude of sea-level pressure variability over the north-western Pacific Ocean and underestimate the variability over northern Africa and southern Europe. They also underestimate the importance of regions such as the Beaufort, East Siberian, and Laptev seas in explaining pan-Arctic summer sea ice area variability, which we hypothesise is due to regional biases in sea ice thickness. Finally, observations show that historically, winter AO events (negatively) covary strongly with summer sea ice concentration in the eastern Pacific sector of the Arctic, although now under a thinning ice regime, both the eastern and western Pacific sectors exhibit similar behaviour. CMIP6 models however do not show this transition on average, which may hinder their ability to make skilful seasonal to inter-annual predictions of summer sea ice. more
Climate Data Records Cryosphere OSI-SAF Validation

New concept of renewable energy priority zones for efficient onshore wind and solar expansion

Author(s):
Sander, Leon; Jung, Christopher; Schindler, Dirk
Publication title: Energy Conversion and Management
2023
 | Volume: 294
2023
DOI: 10.1016/j.enconman.2023.117575
Abstract:
The intensification of climate change impacts requires a fast and efficient transition of energy systems and deployment of renewable energies worldwid… The intensification of climate change impacts requires a fast and efficient transition of energy systems and deployment of renewable energies worldwide. An adequate site assessment strategy forms the basis for expanding installed capacities and energy yield. This study applies a set of meaningful criteria to determine site suitability for Germany's onshore wind and utility-scale solar photovoltaics facilities. An aggregated priority index involving meteorological-technical, economic, and environmental criteria is developed and used in a new concept for identifying renewable energy priority zones, where installations of wind and solar energy facilities should be prioritized. As a novelty, this resource-centered approach does not only analyze the mean energy potential as a meteorological criterion but also accounts for other characteristics such as variability, complementarity, and predictability. The results indicate that reducing legal restrictions substantially facilitates wind and solar energy capacity expansion in prioritized zones. With weak restrictions, up to 22% and 12% of Germany represent priority zones for an efficient and sustainable use of solar and wind energy. However, due to the intermittent nature of wind and solar resources, mismatches between generation potential and electricity demand would persist even with substantial capacity expansion. Future energy systems must advance the expansion of renewable energy capacities just as the flexibilization of demand or an increase of storage capacities to guarantee future energy security and mitigate climate change. The newly developed renewable energy priority zones are a starting point and can be transferred to other study areas by specifically adapting criteria and their weighting. more
Application Atmosphere CM-SAF Climate Data Records

Nitrogen dioxide decline and rebound observed by GOME-2 and TROPOMI during COVID-19 pandemic

Author(s):
Liu, Song; Valks, Pieter; Beirle, Steffen; Loyola, Diego G.
Publication title: Air Quality, Atmosphere & Health
2021
2021
DOI: 10.1007/s11869-021-01046-2
Abstract:
Since its first confirmed case in December 2019, coronavirus disease 2019 (COVID-19) has become a worldwide pandemic with more than 90 million confirm… Since its first confirmed case in December 2019, coronavirus disease 2019 (COVID-19) has become a worldwide pandemic with more than 90 million confirmed cases by January 2021. Countries around the world have enforced lockdown measures to prevent the spread of the virus, introducing a temporal change of air pollutants such as nitrogen dioxide (NO2) that are strongly related to transportation, industry, and energy. In this study, NO2 variations over regions with strong responses to COVID-19 are analysed using datasets from the Global Ozone Monitoring Experiment-2 (GOME-2) sensor aboard the EUMETSAT Metop satellites and TROPOspheric Monitoring Instrument (TROPOMI) aboard the EU/ESA Sentinel-5 Precursor satellite. The global GOME-2 and TROPOMI NO2 datasets are generated at the German Aerospace Center (DLR) using harmonized retrieval algorithms; potential influences of the long-term trend and seasonal cycle, as well as the shortterm meteorological variation, are taken into account statistically. We present the application of the GOME-2 data to analyze the lockdown-related NO2 variations for morning conditions. Consistent NO2 variations are observed for the GOME-2 measurements and the early afternoon TROPOMI data: regions with strong social responses to COVID-19 in Asia, Europe, North America, and South America show strong NO2 reductions of ∼30–50% on average due to restriction of social and economic activities, followed by a gradual rebound with lifted restriction measures. more
AC-SAF Application Atmosphere Climate Data Records

Noise performance of microwave humidity sounders over their lifetime

Author(s):
Hans, Imke; Burgdorf, Martin; John, Viju O.; Mittaz, Jonathan; Buehler, Stefan A.
Publication title: Atmospheric Measurement Techniques
2017
 | Volume: 10 | Issue: 12
2017
DOI: 10.5194/amt-10-4927-2017
Abstract:
Abstract. The microwave humidity sounders Special Sensor Microwave Water Vapor Profiler (SSMT-2), Advanced Microwave Sounding Unit-B (AMSU-B) and Micr… Abstract. The microwave humidity sounders Special Sensor Microwave Water Vapor Profiler (SSMT-2), Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) to date have been providing data records for 25 years. So far, the data records lack uncertainty information essential for constructing consistent long time data series. In this study, we assess the quality of the recorded data with respect to the uncertainty caused by noise. We calculate the noise on the raw calibration counts from the deep space views (DSVs) of the instrument and the noise equivalent differential temperature (NEΔT) as a measure for the radiometer sensitivity. For this purpose, we use the Allan deviation that is not biased from an underlying varying mean of the data and that has been suggested only recently for application in atmospheric remote sensing. Moreover, we use the bias function related to the Allan deviation to infer the underlying spectrum of the noise. As examples, we investigate the noise spectrum in flight for some instruments. For the assessment of the noise evolution in time, we provide a descriptive and graphical overview of the calculated NEΔT over the life span of each instrument and channel. This overview can serve as an easily accessible information for users interested in the noise performance of a specific instrument, channel and time. Within the time evolution of the noise, we identify periods of instrumental degradation, which manifest themselves in an increasing NEΔT, and periods of erratic behaviour, which show sudden increases of NEΔT interrupting the overall smooth evolution of the noise. From this assessment and subsequent exclusion of the aforementioned periods, we present a chart showing available data records with NEΔT \textless 1 K. Due to overlapping life spans of the instruments, these reduced data records still cover without gaps the time since 1994 and may therefore serve as a first step for constructing long time series. Our method for count noise estimation, that has been used in this study, will be used in the data processing to provide input values for the uncertainty propagation in the generation of a new set of Fundamental Climate Data Records (FCDRs) that are currently produced in the project Fidelity and Uncertainty in Climate data records from Earth Observation (FIDUCEO). more
Climate Data Records EUM-Secr Method

Observational Constraint on the Contribution of Surface Albedo Feedback to the Amplified Tibetan Plateau Surface Warming

Author(s):
Chen, Y.; Ji, D.; Moore, J.C.; Hu, J.; He, Y.
Publication title: Journal of Geophysical Research: Atmospheres
2022
 | Volume: 127 | Issue: 13
2022
DOI: 10.1029/2021JD036085
Abstract:
Surface albedo feedback (SAF) is one of the main causes of amplified warming over the Tibetan Plateau (TP). Several recent studies have used the lates… Surface albedo feedback (SAF) is one of the main causes of amplified warming over the Tibetan Plateau (TP). Several recent studies have used the latest reanalysis datasets to evaluate the SAF induced warming, but without fully considering the fidelity of the surface albedo change and surface downward solar radiation in the reanalysis datasets, which directly affect the amplitude of SAF induced warming. This study finds that the state-of-the-art reanalysis datasets (ERA-Interim, ERA5, MERRA, MERRA-2, JRA-55 and CRA) and climate models that participated in the Coupled Model Intercomparison Project Phase 6 (CMIP6) exhibit varying biases compared with observations in both surface albedo change and surface downward solar radiation over the TP. The state-of-the-art reanalysis datasets present no obvious advantages over the lower resolution but less constrained CMIP6 multi-model ensemble in representing SAF related processes over the TP. The surface albedo change drives most of the spread in SAF induced warming. The reanalysis datasets and CMIP6 climate models reveal a significant linear relationship between surface albedo change and its contribution to surface temperature change over the TP. Using the observation constrained linear relationship and satellite surface albedo products, the spread of warming contribution due to SAF in reanalysis datasets and climate models is greatly reduced, the estimated TP warming due to SAF is in the range of 0.26–0.50 K in winter and 0.27–0.77 K in spring over recent decades. © 2022. American Geophysical Union. All Rights Reserved. more
CM-SAF Climate Data Records Land Validation

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
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