HOAPS and ERA-Interim precipitation over sea: Validation against shipboard in-situ measurements

Gert.Koenig-Langlo [ at ] awi.de


The satellite derived HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data) and ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis data sets have been validated against in-situ precipitation measurements from ship rain gauges and optical disdrometers over the open-ocean by applying a statistical analysis for binary forecasts. For this purpose collocated pairs of data were merged within a certain temporal and spatial threshold into single events, according to the satellites' overpass, the observation and the forecast times. HOAPS detects the frequency of precipitation well, while ERA-Interim strongly overestimates it, especially in the tropics and subtropics. Although precipitation rates are difficult to compare because along-track point measurements are collocated with areal estimates and the numbers of available data are limited, we find that HOAPS underestimates precipitation rates, while ERA-Interim's Atlantic-wide average precipitation rate is close to measurements. However, regionally averaged over latitudinal belts, there are deviations between the observed mean precipitation rates and ERA-Interim. The most obvious ERA-Interim feature is an overestimation of precipitation in the area of the intertropical convergence zone and the southern sub-tropics over the Atlantic Ocean. For a limited number of snow measurements by optical disdrometers it can be concluded that both HOAPS and ERA-Interim are suitable to detect the occurrence of solid precipitation.

Item Type
Primary Division
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Research Networks
Publication Status
Eprint ID
DOI 10.5194/amt-2016-22

Cite as
Bumke, K. , König-Langlo, G. , Kinzel, J. and Schröder, M. (2016): HOAPS and ERA-Interim precipitation over sea: Validation against shipboard in-situ measurements , Atmospheric Measurement Techniques (AMT), 9(5):2 . doi: 10.5194/amt-2016-22

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