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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Autores principales:	Meri Virman, Marja Bister, Jouni Räisänen, Victoria A. Sinclair, Heikki Järvinen
Formato:	article
Lenguaje:	EN
Publicado:	Taylor & Francis Group 2021
Materias:	radiosonde observations era5 era-interim temperature moisture Oceanography GC1-1581 Meteorology. Climatology QC851-999
Acceso en línea:	https://doaj.org/article/7b87ffa156c24608b371c6ef007a1c8f
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spelling	oai:doaj.org-article:7b87ffa156c24608b371c6ef007a1c8f2021-12-01T14:40:58ZRadiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans1600-087010.1080/16000870.2021.1929752https://doaj.org/article/7b87ffa156c24608b371c6ef007a1c8f2021-01-01T00:00:00Zhttp://dx.doi.org/10.1080/16000870.2021.1929752https://doaj.org/toc/1600-0870After 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.Meri VirmanMarja BisterJouni RäisänenVictoria A. SinclairHeikki JärvinenTaylor & Francis Grouparticleradiosonde observationsera5era-interimtemperaturemoistureOceanographyGC1-1581Meteorology. ClimatologyQC851-999ENTellus: Series A, Dynamic Meteorology and Oceanography, Vol 73, Iss 1, Pp 1-7 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	radiosonde observations era5 era-interim temperature moisture Oceanography GC1-1581 Meteorology. Climatology QC851-999
spellingShingle	radiosonde observations era5 era-interim temperature moisture Oceanography GC1-1581 Meteorology. Climatology QC851-999 Meri Virman Marja Bister Jouni Räisänen Victoria A. Sinclair Heikki Järvinen Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans
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.
format	article
author	Meri Virman Marja Bister Jouni Räisänen Victoria A. Sinclair Heikki Järvinen
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
publishDate	2021
url	https://doaj.org/article/7b87ffa156c24608b371c6ef007a1c8f
work_keys_str_mv	AT merivirman radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT marjabister radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT jouniraisanen radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT victoriaasinclair radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans AT heikkijarvinen radiosondecomparisonofera5anderainterimreanalysisdatasetsovertropicaloceans
_version_	1718405001359917056

Radiosonde comparison of ERA5 and ERA-Interim reanalysis datasets over tropical oceans

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