Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans
After the release of the ERA-Interim reanalysis, many changes have been made to the Integrated Forecasting System model and data-assimilation system, resulting in an improved reanalysis, ERA5. One of the changes in the model allows the model version in ERA5 to represent the moisture sensitivity of d...
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doaj-7b87ffa156c24608b371c6ef007a1c8f2021-06-02T08:05:32ZengTaylor & Francis GroupTellus: Series A, Dynamic Meteorology and Oceanography1600-08702021-01-017311710.1080/16000870.2021.19297521929752Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceansMeri Virman0Marja Bister1Jouni Räisänen2Victoria A. Sinclair3Heikki Järvinen4Institute for Atmospheric and Earth System Research (INAR), University of HelsinkiInstitute for Atmospheric and Earth System Research (INAR), University of HelsinkiInstitute for Atmospheric and Earth System Research (INAR), University of HelsinkiInstitute for Atmospheric and Earth System Research (INAR), University of HelsinkiInstitute for Atmospheric and Earth System Research (INAR), University of HelsinkiAfter the release of the ERA-Interim reanalysis, many changes have been made to the Integrated Forecasting System model and data-assimilation system, resulting in an improved reanalysis, ERA5. One of the changes in the model allows the model version in ERA5 to represent the moisture sensitivity of deep convection more realistically than the model version in ERA-Interim. A previous modeling study showed that this change alone improved the representation of the tropical atmosphere, e.g. tropical variability and precipitation distribution. Here we compare the vertical structures of average temperature and moisture over tropical oceans in ERA5, ERA-Interim and radiosonde observations to see whether ERA5 is also closer to observations for those regions and variables. Our results reveal that at many levels, temperature and relative humidity in ERA5 and ERA-Interim differ from observations, however ERA-Interim is generally closer to observations than ERA5 in the low-to-midtroposphere. Most notably, in many stations, ERA5 is on average colder than observations at ∼550-800 hPa. Large vertical gradients occur in the profile of the mean temperature difference between ERA5 and observations at ∼700-900 hPa, but are absent in ERA-Interim. Relative humidity differences are not as robust as temperature differences, however in many stations ERA5 is on average moister than observations at ∼650-800 hPa while ERA-Interim is closer to observations there. Below the ∼950 hPa-level ERA5 and ERA-Interim are generally colder and moister than observations. Our results indicate that ERA5 deviates more than ERA-Interim from tropical radiosonde observations in the low-to-midtroposphere. It seems plausible that this deviation is, at least partly, due to the newer formulation of organised deep entrainment in ERA5 and the associated mechanism for the moisture sensitivity. However, more extensive model evaluation is needed to understand the reasons for the differences between the reanalyses and radiosonde observations.http://dx.doi.org/10.1080/16000870.2021.1929752radiosonde observationsera5era-interimtemperaturemoisture |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Meri Virman Marja Bister Jouni Räisänen Victoria A. Sinclair Heikki Järvinen |
spellingShingle |
Meri Virman Marja Bister Jouni Räisänen Victoria A. Sinclair Heikki Järvinen Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans Tellus: Series A, Dynamic Meteorology and Oceanography radiosonde observations era5 era-interim temperature moisture |
author_facet |
Meri Virman Marja Bister Jouni Räisänen Victoria A. Sinclair Heikki Järvinen |
author_sort |
Meri Virman |
title |
Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans |
title_short |
Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans |
title_full |
Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans |
title_fullStr |
Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans |
title_full_unstemmed |
Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans |
title_sort |
radiosonde comparison of era5 and era-interim reanalysis datasets over tropical oceans |
publisher |
Taylor & Francis Group |
series |
Tellus: Series A, Dynamic Meteorology and Oceanography |
issn |
1600-0870 |
publishDate |
2021-01-01 |
description |
After the release of the ERA-Interim reanalysis, many changes have been made to the Integrated Forecasting System model and data-assimilation system, resulting in an improved reanalysis, ERA5. One of the changes in the model allows the model version in ERA5 to represent the moisture sensitivity of deep convection more realistically than the model version in ERA-Interim. A previous modeling study showed that this change alone improved the representation of the tropical atmosphere, e.g. tropical variability and precipitation distribution. Here we compare the vertical structures of average temperature and moisture over tropical oceans in ERA5, ERA-Interim and radiosonde observations to see whether ERA5 is also closer to observations for those regions and variables. Our results reveal that at many levels, temperature and relative humidity in ERA5 and ERA-Interim differ from observations, however ERA-Interim is generally closer to observations than ERA5 in the low-to-midtroposphere. Most notably, in many stations, ERA5 is on average colder than observations at ∼550-800 hPa. Large vertical gradients occur in the profile of the mean temperature difference between ERA5 and observations at ∼700-900 hPa, but are absent in ERA-Interim. Relative humidity differences are not as robust as temperature differences, however in many stations ERA5 is on average moister than observations at ∼650-800 hPa while ERA-Interim is closer to observations there. Below the ∼950 hPa-level ERA5 and ERA-Interim are generally colder and moister than observations. Our results indicate that ERA5 deviates more than ERA-Interim from tropical radiosonde observations in the low-to-midtroposphere. It seems plausible that this deviation is, at least partly, due to the newer formulation of organised deep entrainment in ERA5 and the associated mechanism for the moisture sensitivity. However, more extensive model evaluation is needed to understand the reasons for the differences between the reanalyses and radiosonde observations. |
topic |
radiosonde observations era5 era-interim temperature moisture |
url |
http://dx.doi.org/10.1080/16000870.2021.1929752 |
work_keys_str_mv |
AT merivirman radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT marjabister radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT jouniraisanen radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT victoriaasinclair radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT heikkijarvinen radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans |
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1721406711049224192 |