Mecking, Rebekka

German

The objective of this thesis is to verify the qualitative and quantitative influence of the weather on precipitation data over the Baltic Sea, derived from the HOAPS climatology  (Hamburg Ocean Atmosphere Parameters and fluxes from Satellite Data), and to analyze the synoptic phenomena that may influence the probability of HOAPS to detect precipitation. For this purpose, precipitation data of the HOAPS climatology derived from satellite measurements as well as in-situ-precipitation measurements by ship rain gauges on board of merchant ships, both taken in a period between 1995 and 1997, are available. The data set is collocated; the HOAPS- and the rain gauge measurements are separated by 30 minutes and 25 kilometers at most. In order to analyze the weather conditions, the prognostic Europamodell of the DWD as well as surface pressure charts and satellite images were used. On average, HOAPS detects 55% of all precipitation events having precipitation rates greater equal 0.3mm/h that are identified by the ship rain gauges as well. The comparison of the precipitation data leads to the conclusion that HOAPS underestimates the measured precipitation; the inclusion of weather charts and satellite images shows that this is independent of the type of precipitation. Moreover, the probability of HOAPS to identify precipitation rises when precipitation rates rise. The investigation of cloud types, pressure fields and frontal systems shows that the probability of HOAPS to detect precipitation is smaller during convective than during stratiform clouds; correspondingly, a passage of a cold front also decreases the probability of HOAPS to identify precipitation. Thus, it may be concluded that HOAPS misses short-period precipitation like showers more often than long-lasting, stratiform precipitation

Einfluss der synoptischen Situation auf die Validierung von Niederschlägen aus Satellitendaten über der Ostsee

Abstract

Similar works

Full text

Available Versions

OceanRep