Frank Kaspar | Deutscher Wetterdienst (original) (raw)

Papers by Frank Kaspar

Bulletin of the American Meteorological Society, Feb 1, 2018

The CORE-CLIMAX project has delivered methods and assessments of the capability to provide climat... more The CORE-CLIMAX project has delivered methods and assessments of the capability to provide climate data records, processes for deriving and validating these records, and opportunities to feed back the lessons learned from reanalysis.

EGU General Assembly Conference Abstracts, Apr 1, 2018

A new satellite-derived climate dataset-denoted CLARA-A1 ("The CM SAF cLoud, Albedo and RAdiation... more A new satellite-derived climate dataset-denoted CLARA-A1 ("The CM SAF cLoud, Albedo and RAdiation dataset from AVHRR data")-is described. The dataset covers the 28-yr period from 1982 until 2009 and consists of cloud, surface albedo and radiation budget products derived from the AVHRR (Advanced Very High Resolution Radiometer) sensor carried by polar orbiting operational meteorological satellites. Its content, anticipated accuracies, limitations and potential applications are described. The dataset is produced by the EUMETSAT Climate Monitoring Satellite Application Facility (CM SAF) project. The dataset has its strengths in the long duration, its foundation upon a homogenized AVHRR radiance data record, and in some unique features, e.g. the availability of 28 yr of summer surface albedo and cloudiness parameters over the polar regions. Quality characteristics are also well investigated and particularly useful results can be found over the tropics, mid-to high-latitudes and over nearly all oceanic areas. Being the first CM SAF dataset of its kind, an intensive evaluation of the quality of the datasets was performed and major findings wrt. to merits and shortcomings of the datasets are reported. However, the CM SAF's long-term commitment to perform two additional reprocessing events within the time frame 2013-2017 will allow a proper handling of limitations as well as upgrading the dataset with new features (e.g. uncertainty estimates) and extension of the temporal coverage.

Atmospheric Chemistry and Physics, May 28, 2013

A new satellite-derived climate dataset-denoted CLARA-A1 ("The CM SAF cLoud, Albedo and RAdiation... more A new satellite-derived climate dataset-denoted CLARA-A1 ("The CM SAF cLoud, Albedo and RAdiation dataset from AVHRR data")-is described. The dataset covers the 28 yr period from 1982 until 2009 and consists of cloud, surface albedo, and radiation budget products derived from the AVHRR (Advanced Very High Resolution Radiometer) sensor carried by polar-orbiting operational meteorological satellites. Its content, anticipated accuracies, limitations, and potential applications are described. The dataset is produced by the EUMETSAT Climate Monitoring Satellite Application Facility (CM SAF) project. The dataset has its strengths in the long duration, its foundation upon a homogenized AVHRR radiance data record, and in some unique features, e.g. the availability of 28 yr of summer surface albedo and cloudiness parameters over the polar regions. Quality characteristics are also well investigated and particularly useful results can be found over the tropics, mid to high latitudes and over nearly all oceanic areas. Being the first CM SAF dataset of its kind, an intensive evaluation of the quality of the datasets was performed and major findings with regard to merits and shortcomings of the datasets are reported. However, the CM SAF's long-term commitment to perform two additional reprocessing events within the time frame 2013-2018 will allow proper handling of limitations as well as upgrading the dataset with new features (e.g. uncertainty estimates) and extension of the temporal coverage.

Extreme precipitation is a weather phenomenon with tremendous damaging potential for property and... more Extreme precipitation is a weather phenomenon with tremendous damaging potential for property and human life. As the intensity and frequency of such events is projected to increase in a warming climate, there is an urgent need to advance the existing knowledge on extreme precipitation processes, statistics and impacts across scales. To this end, a working group within the Germany-based project, ClimXtreme, has been established to carry out multidisciplinary analyses of high-impact events. In this work, we provide a comprehensive assessment of the 29 June 2017 heavy precipitation event (HPE) affecting the Berlin metropolitan region (Germany), from the meteorological, impacts and climate perspectives, including climate change attribution. Our analysis showed that this event occurred under the influence of a mid-tropospheric trough over western Europe and two shortwave surface lows over Britain and Poland (Rasmund and Rasmund II), inducing relevant low-level wind convergence along the German-Polish border. Over 11 000 convective cells were triggered, starting early morning 29 June, displacing northwards slowly under the influence of a weak tropospheric flow (10 m s −1 at 500 hPa). The quasi-stationary situation led to totals up to 196 mm d −1 , making this event the 29 June most severe in the 1951-2021 climatology, ranked by means of a precipitation-based index. Regarding impacts, it incurred the largest insured losses in the period 2002 to 2017 (EUR 60 million) in the greater Berlin area. We provide further insights on flood attributes (inundation, depth, duration) based on a unique household-level survey data set. The major moisture source for this event was the Alpine-Slovenian region (63 % of identified sources) Published by Copernicus Publications on behalf of the European Geosciences Union. 3702 A. Caldas-Alvarez et al.: Meteorological, impact and climate perspectives of the 29 June 2017 event due to recycling of precipitation falling over that region 1 d earlier. Implementing three different generalised extreme value (GEV) models, we quantified the return periods for this case to be above 100 years for daily aggregated precipitation, and up to 100 and 10 years for 8 and 1 h aggregations, respectively. The conditional attribution demonstrated that warming since the pre-industrial era caused a small but significant increase of 4 % in total precipitation and 10 % for extreme intensities. The possibility that not just greenhousegas-induced warming, but also anthropogenic aerosols affected the intensity of precipitation is investigated through aerosol sensitivity experiments. Our multidisciplinary approach allowed us to relate interconnected aspects of extreme precipitation. For instance, the link between the unique meteorological conditions of this case and its very large return periods, or the extent to which it is attributable to alreadyobserved anthropogenic climate change.

Biodiversity & Ecology, 2018

Climate change and adaptive land management in southern Africa-assessments, changes, challenges, ... more Climate change and adaptive land management in southern Africa-assessments, changes, challenges, and solutions. Biodiversity & Ecology, 6, Klaus Hess Publishers, Göttingen & Windhoek.

Promet-traffic & Transportation, 2020

Advances in Science and Research, 2015

Reanalysis near-surface wind fields from multiple reanalyses are potentially an important informa... more Reanalysis near-surface wind fields from multiple reanalyses are potentially an important information source for wind energy applications. Inter-comparing reanalyses via employing independent observations can help to guide users to useful spatio-temporal scales. Here we compare the statistical properties of wind speeds observed at 210 traditional meteorological stations over Germany with the reanalyses' near-surface fields, confining the analysis to the recent years (2007 to 2010). In this period, the station time series in Germany can be expected to be mostly homogeneous. We compare with a regional reanalysis (COSMO-REA6) and two global reanalyses, ERA-Interim and ERA-20C. We show that for the majority of the stations, the Weibull parameters of the daily mean wind speed frequency distribution match remarkably well with the ones derived from the reanalysis fields. High correlations (larger than 0.9) can be found between stations and reanalysis monthly mean wind speeds all over Germany. Generally, the correlation between the higher resolved COSMO-REA6 wind fields and station observations is highest, for both assimilated and non-assimilated (i.e., independent) observations. As expected from the lower spatial resolution and reduced amount of data assimilated into ERA-20C, the correlation of monthly means decreases somewhat relative to the other reanalyses (in our investigated period of 2007 to 2010). Still, the inter-annual variability connected to the North Atlantic Oscillation (NAO) found in the reanalysis surface wind anomalies is in accordance with the anomalies recorded by the stations. We discuss some typical examples where differences are found, e.g., where the mean wind distributions differ (probably related to either height or model topography differences) and where the correlations break down (because of unresolved local topography) which applies to a minority of stations. We also identified stations with homogeneity problems in the reported station values, demonstrating how reanalyses can be applied to support quality control for the observed station data. Finally, as a demonstration of concept, we discuss how comparing feedback files of the different reanalyses can guide users to useful scales of variability.

Advances in Science and Research, 2015

A web-based survey to assess the benefits and gaps in reanalyses as part of growing climate servi... more A web-based survey to assess the benefits and gaps in reanalyses as part of growing climate services was carried out in 2013-2014. The survey elicited responses from about 2500 users of climate information. One of the eleven survey points specifically addressed the observations used in reanalysis, with a multiple-choice question "Have you used reanalysis input observations and feedback data?". Almost half of the respondents admitted to not knowing what such data were about. Among the others, specific queries asked for these observations to be made available more openly. This paper summarizes the main findings in regard to use of existing reanalyses as well as user awareness and needs in regard to reanalysis feedback data and input observations. In the future, the information obtained via the survey makes it possible to perform various statistically robust analyses addressing different aspects of the use of reanalysis data.

Umwelt- und Gesundheitsschäden durch die Stromerzeugung, 1997

Vorrangiges Ziel dieses Kapitels ist die Abschatzung der externen Kosten der Stromerzeugung mit P... more Vorrangiges Ziel dieses Kapitels ist die Abschatzung der externen Kosten der Stromerzeugung mit Photovoltaik und Windenergie fur deutsche Referenzumgebungen. Dabei wurden im wesentlichen die Methoden angewendet, die auch bei der Untersuchung der fossilen Energietrager zum Einsatz kamen. 5.1 Photovoltaik Dieser Abschnitt analysiert und quantifiziert Ursachen und Auswirkungen von Belastungen, die durch die Photovoltaik auftreten. Produktions-und Betriebsphase wurden berucksichtigt. Luftschadstoffemissionen der Produktionsphase wurden bestimmt und die zugehorigen Schaden an offentlicher Gesundheit, Getreide, Waldern, Materialoberflachen und dem globalen Klimasystem abgeschatzt. Berufliche Gesundheitsrisiken wurden auf Basis von Statistiken bestimmt. Fur all diese Schaden werden, basierend auf den Ergebnissen der gesamten Studie, monetare Werte angegeben. 5.1.1 Eigenschaften der photovoltaischen Energieversorgung 5.1.1.1 Allgemeines Bei der Betrachtung erneuerbarer Energien sind einige Besonderheiten zu berucksichtigen, die einen direkten Vergleich mit konventionellen, zentralen Kraftwerken erschweren. Aufgrund der dezentralen Struktur der photovoltaischen Energieversorgung gibt es einige konzeptionelle Schwierigkeiten bei der Anwendung der allgemein akzeptierten Grenzschadensmethode auf einzelne kleine Systerne an einem festgelegten Referenzstandort. Da sich die Photovoltaik in der Entwicklungsphase befindet, sind bei verschiedenen Anlagen relativ groBe Abweichungen festzustellen. Urn derartige Schwierigkeiten zu bewaltigen, werden zusatzlich zur Untersuchung der Referenzstandorte Vergleiche mit dem deutschen "lOOO-Dacher-Programm" durchgefUhrt. Die dort verfUgbaren Daten werden zum Ausgleich extremer Abweichungen der Einzelanlagen genutzt, so daB die Ergebnisse eine allgemeine Giiltigkeit fUr PV-Anlagen in Deutschland haben.

The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) uses space-based obser... more The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) uses space-based observations from both geostationary satellites (Meteosat Second Generation, MSG) and polar orbiting satellites (NOAA, MetOp, DMSP) to provide data sets of geophysical parameters suitable for climate analysis and monitoring. A substantial part of this initiative is related to clouds and corresponding satellite-derived parameters, such as cloud fractional coverage, cloud top parameters, cloud optical depth, effective radius, cloud phase, and cloud water path. Due to recurring efforts of incorporating revised retrieval schemes and new radiance inter-calibration and homogenization, the processing system is periodically maintained and updated. Recently, the CM SAF cloud datasets were reprocessed using the latest retrieval developments and homogenized radiances. They span time periods of 28 years for AVHRR GAC, and 7 years for SEVIRI, respectively. The latter with very high temporal resolution. Besides other existing datasets, e.g. Patmos-X (Heidinger et al., 2005), ISCCP (Rossow and Schiffer, 1999), and MODIS-(Platnick et al., 2003), microwave-and IR-sounder-based cloud climatologies, the CM SAF datasets of cloud properties complement the international effort of analysing and understanding clouds and their spatiotemporal variations and long-term variability. The CM SAF datasets allow for investigations of process studies and the general long-term cloud analysis with respect to the time period covered. The reprocessed and homogenized data will support the assessment of possible occurring global or regional trends, and of cyclic variations of cloud parameters at different time scales. Among other applications, these data sets are therefore a proper reference to assess the quality of global climate simulations. This presentation will give an overview over the cloud products and corresponding datasets, as processed by the CM SAF. Validation results and examples of applications will be shown for the AVHRR GAC dataset. Further, we will give an outlook on future CM SAF activities, which will additionally focus on the generation of cloud properties derived from TOVS and ATOVS, and derived from multiple generations of geostationary instruments.

EGS General Assembly Conference Abstracts, 2002

WaterGAP 2 is an integrated global model of water use and water availability. The hydrologic subm... more WaterGAP 2 is an integrated global model of water use and water availability. The hydrologic submodel (WGHM) computes surface runoff, groundwater recharge and river discharge at a spatial resolution of 0.5 degree. It is calibrated against observed discharge at 724 gauging stations which represent about 50% of the global land area. The model has been used in a number of studies to assess the effects of a chang- ing climate on water resources. The results of global climate models have been used as input for these scenario calculations. Due to the calibration the hydrologic model performs quite well for simulations of historic periods. An uncertainty analysis has been performed to evaluate the reliability of the scenario calculations. Three sources of uncertainties have been considered: (1) the uncertainty of the internal model pa- rameters, (2) the uncertainty caused by the use of different climate models and (3) the uncertainty due to the model structure. For the first category 38 model parameters have been considered with their appropriate probability distributions derived from lit- erature research. Latin Hypercube sampling has been used to evaluate the effect on the model output. Two climate models (ECHAM4 and HadCM3) have been used to demonstrate the effects of category 2. The third type of uncertainties was evaluated by comparing two approaches for the evapotranspiration equation (Priestley-Taylor vs. Penman-Monteith. The results are presented in a way that allows a direct comparison of the different sources of uncertainties. The analysis has been performed in different water basins all over the world. This reveals significant regional differences in the im- portance of the different sources of uncertainties. A comparison of basins with their subbasins demonstrates the relevance of the spatial scale.

Frontiers in Climate

Reliable weather observations are the basis to assess climate change and variability. Compared to... more Reliable weather observations are the basis to assess climate change and variability. Compared to other regions of the world, long time series of weather observations are sparse in many countries of Sub-Saharan Africa. Various activities at national or international level are ongoing to improve the availability and quality of climate databases. Here, we present ongoing international contributions with a focus on representative examples hosted at Germany's national meteorological service DWD (Deutscher Wetterdienst). The international exchange of monthly climate reports (CLIMAT) is monitored within the Monitoring Centre of the GCOS Surface Network (Global Climate Observing System). In that context also quality control is performed and data are made publicly available. Recent climate observations can be complemented by digitization of historical hand-written weather observations which are available in distributed archives. International data centers, such as the Global Precipitati...

&lt;p&gt;In recent years, the DWD has significantly expanded free access to its c... more &lt;p&gt;In recent years, the DWD has significantly expanded free access to its climate observations. A first step was a simple FTP site with the possibility to download archives with different data categories, e.g. national and international station-based meteorological data, derived parameters, gridded products, and special categories like phenological data. The data are based on the DWD's observation systems for Germany as well as on the DWD's international activities.&lt;/p&gt;&lt;p&gt;Based on the consistent implementation of OGC standards, an interactive and user-friendly access to the data has been created with the development of the DWD climate portal.&lt;/p&gt;&lt;p&gt;In addition to browsing, previewing, running basic analysis and downloading the data, the available OGC services enable users to set up their own services on the DWD data. Along with the free and extended access to the data and services, the users' demands on the availability, quality, and detail of the metadata also increased significantly. Maintaining and linking metadata to the opendata and services remains a challenge. However, INSPIRE and WIGOS are paving the way to a unified solution and overcoming the problems.&lt;/p&gt;&lt;p&gt;Another challenging requirement was to provide interactive access to long time series from gridded products to the users. To accomplish this, we have moved away from a previously file-based approach to storing the raster data as a georaster in an Oracle database. This design allows us a combined analysis of raster and station data not only in the climate data portal but also in the central climate database.&lt;/p&gt;&lt;p&gt;The presentation will provide a technical and functional overview of the DWD climate data portal.&lt;/p&gt;

Bulletin of the American Meteorological Society, Feb 1, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2018

Atmospheric Chemistry and Physics, May 28, 2013

A new satellite-derived climate dataset-denoted CLARA-A1 ("The CM SAF cLoud, Albedo and RAdiation... more A new satellite-derived climate dataset-denoted CLARA-A1 ("The CM SAF cLoud, Albedo and RAdiation dataset from AVHRR data")-is described. The dataset covers the 28 yr period from 1982 until 2009 and consists of cloud, surface albedo, and radiation budget products derived from the AVHRR (Advanced Very High Resolution Radiometer) sensor carried by polar-orbiting operational meteorological satellites. Its content, anticipated accuracies, limitations, and potential applications are described. The dataset is produced by the EUMETSAT Climate Monitoring Satellite Application Facility (CM SAF) project. The dataset has its strengths in the long duration, its foundation upon a homogenized AVHRR radiance data record, and in some unique features, e.g. the availability of 28 yr of summer surface albedo and cloudiness parameters over the polar regions. Quality characteristics are also well investigated and particularly useful results can be found over the tropics, mid to high latitudes and over nearly all oceanic areas. Being the first CM SAF dataset of its kind, an intensive evaluation of the quality of the datasets was performed and major findings with regard to merits and shortcomings of the datasets are reported. However, the CM SAF's long-term commitment to perform two additional reprocessing events within the time frame 2013-2018 will allow proper handling of limitations as well as upgrading the dataset with new features (e.g. uncertainty estimates) and extension of the temporal coverage.

Biodiversity & Ecology, 2018

Promet-traffic & Transportation, 2020

Advances in Science and Research, 2015

Umwelt- und Gesundheitsschäden durch die Stromerzeugung, 1997

EGS General Assembly Conference Abstracts, 2002

Frontiers in Climate