Remote sensing of cloud liquid water
A method is presented to infer cloud liquid water path (LWP in kg/m2) over the ocean from passive microwave measurements of SSM/I. The algorithm to retrieve LWP is based on simulated satellite observations. They are calculated with a radiative transfer model applied to about 3000 radiosonde ascents...
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ftoceanrep:oai:oceanrep.geomar.de:44033 2023-05-15T18:18:52+02:00 Remote sensing of cloud liquid water Karstens, U. Simmer, Clemens Ruprecht, Eberhard 1994 text https://oceanrep.geomar.de/id/eprint/44033/ https://oceanrep.geomar.de/id/eprint/44033/1/10.1007_BF01030057.pdf https://doi.org/10.1007/BF01030057 en eng Springer https://oceanrep.geomar.de/id/eprint/44033/1/10.1007_BF01030057.pdf Karstens, U., Simmer, C. and Ruprecht, E. (1994) Remote sensing of cloud liquid water. Meteorology and Atmospheric Physics, 54 (1-4). pp. 157-171. DOI 10.1007/BF01030057 <https://doi.org/10.1007/BF01030057>. doi:10.1007/BF01030057 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 1994 ftoceanrep https://doi.org/10.1007/BF01030057 2023-04-07T15:40:50Z A method is presented to infer cloud liquid water path (LWP in kg/m2) over the ocean from passive microwave measurements of SSM/I. The algorithm to retrieve LWP is based on simulated satellite observations. They are calculated with a radiative transfer model applied to about 3000 radiosonde ascents over the Atlantic Ocean. Since radiosonde observations do not contain direct information about cloud water and ice, these parameters are parameterized based on relative humidity and temperature using modified adiabatic liquid water density profiles. A multiple linear regression is applied to the simulated radiances and the calculated LWP to derive the algorithm. The retrieval accuracy based on the regression analysis including instrumental noise is 0.03 kg/m2. Validation of the LWP-algorithm was pursued through a comparison with measurements of a ground-based 33 GHzmicrowave radiometer on board of R.V. “Poseidon” during the International Cirrus Experiment 1989 at the North Sea (ICE'89). The LWP values agree within the range of uncertainty caused by the different sampling characteristics of the observing systems. The retrieval accuracy for clear-sky cases determined using colocated METEOSAT data over the North Sea is 0.037 kg/m2 and confirms the accuracy estimated from regression analysis for the low liquid water cases. The algorithm was used to derive maps of monthly mean LWP over the Atlantic Ocean. As an example the Octobers of the 5 years 1987–1991 were selected to demonstrate the interannual variability of LWP. The results were compared with the cloud water content produced by the climate model ECHAM-T2 from the Max-Planck-Institut Hamburg. Observations during ICE'89 were used to check the accuracy of the applied radiative transfer model. Brightness temperatures were calculated from radiosonde ascents launched during the overpass of DMSP-F8 in cloud-free situations. The channel-dependent differences range from about −2 to 3 K. The possibility to identify different cloud types using microwave and infrared ... Article in Journal/Newspaper Sea ice OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Meteorology and Atmospheric Physics 54 1-4 157 171 |
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Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
A method is presented to infer cloud liquid water path (LWP in kg/m2) over the ocean from passive microwave measurements of SSM/I. The algorithm to retrieve LWP is based on simulated satellite observations. They are calculated with a radiative transfer model applied to about 3000 radiosonde ascents over the Atlantic Ocean. Since radiosonde observations do not contain direct information about cloud water and ice, these parameters are parameterized based on relative humidity and temperature using modified adiabatic liquid water density profiles. A multiple linear regression is applied to the simulated radiances and the calculated LWP to derive the algorithm. The retrieval accuracy based on the regression analysis including instrumental noise is 0.03 kg/m2. Validation of the LWP-algorithm was pursued through a comparison with measurements of a ground-based 33 GHzmicrowave radiometer on board of R.V. “Poseidon” during the International Cirrus Experiment 1989 at the North Sea (ICE'89). The LWP values agree within the range of uncertainty caused by the different sampling characteristics of the observing systems. The retrieval accuracy for clear-sky cases determined using colocated METEOSAT data over the North Sea is 0.037 kg/m2 and confirms the accuracy estimated from regression analysis for the low liquid water cases. The algorithm was used to derive maps of monthly mean LWP over the Atlantic Ocean. As an example the Octobers of the 5 years 1987–1991 were selected to demonstrate the interannual variability of LWP. The results were compared with the cloud water content produced by the climate model ECHAM-T2 from the Max-Planck-Institut Hamburg. Observations during ICE'89 were used to check the accuracy of the applied radiative transfer model. Brightness temperatures were calculated from radiosonde ascents launched during the overpass of DMSP-F8 in cloud-free situations. The channel-dependent differences range from about −2 to 3 K. The possibility to identify different cloud types using microwave and infrared ... |
format |
Article in Journal/Newspaper |
author |
Karstens, U. Simmer, Clemens Ruprecht, Eberhard |
spellingShingle |
Karstens, U. Simmer, Clemens Ruprecht, Eberhard Remote sensing of cloud liquid water |
author_facet |
Karstens, U. Simmer, Clemens Ruprecht, Eberhard |
author_sort |
Karstens, U. |
title |
Remote sensing of cloud liquid water |
title_short |
Remote sensing of cloud liquid water |
title_full |
Remote sensing of cloud liquid water |
title_fullStr |
Remote sensing of cloud liquid water |
title_full_unstemmed |
Remote sensing of cloud liquid water |
title_sort |
remote sensing of cloud liquid water |
publisher |
Springer |
publishDate |
1994 |
url |
https://oceanrep.geomar.de/id/eprint/44033/ https://oceanrep.geomar.de/id/eprint/44033/1/10.1007_BF01030057.pdf https://doi.org/10.1007/BF01030057 |
genre |
Sea ice |
genre_facet |
Sea ice |
op_relation |
https://oceanrep.geomar.de/id/eprint/44033/1/10.1007_BF01030057.pdf Karstens, U., Simmer, C. and Ruprecht, E. (1994) Remote sensing of cloud liquid water. Meteorology and Atmospheric Physics, 54 (1-4). pp. 157-171. DOI 10.1007/BF01030057 <https://doi.org/10.1007/BF01030057>. doi:10.1007/BF01030057 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1007/BF01030057 |
container_title |
Meteorology and Atmospheric Physics |
container_volume |
54 |
container_issue |
1-4 |
container_start_page |
157 |
op_container_end_page |
171 |
_version_ |
1766195620167548928 |