Arctic Ocean Precipitation From Atmospheric Reanalyses and Comparisons With North Pole Drifting Station Records
We evaluate fields of Arctic Ocean precipitation from six atmospheric reanalyses: NASA MERRA, NASA MERRA2, NOAA CFSR/CFSv2, ECMWF ERA‐Interim, ECMWF ERA5, and JMAO JRA55. The study is motivated by recognition that precipitation fields from reanalyses can serve as the key input into snow on sea ice a...
| Main Authors: | , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
American Geophysical Union (AGU)
2020
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| Subjects: | |
| Online Access: | https://discovery.ucl.ac.uk/id/eprint/10095045/1/2019JC015709.pdf https://discovery.ucl.ac.uk/id/eprint/10095045/ |
| Summary: | We evaluate fields of Arctic Ocean precipitation from six atmospheric reanalyses: NASA MERRA, NASA MERRA2, NOAA CFSR/CFSv2, ECMWF ERA‐Interim, ECMWF ERA5, and JMAO JRA55. The study is motivated by recognition that precipitation fields from reanalyses can serve as the key input into snow on sea ice accumulation models, supporting retrievals of sea ice thickness from satellite altimeter systems. Time series of annual precipitation over the central Arctic Ocean correlate well between all reanalyses, and they all capture the basic spatial and seasonal patterns of Arctic precipitation. However, they differ strongly with respect to precipitation amount: CFSR and MERRA2 are wetter than the other reanalyses. All reanalyses depict that the majority of total annual precipitation over the central Arctic Ocean comes from small events, less than 1 mm/day. Validation is challenged by sparse observations, uncertain adjustments for gauge undercatch, and other issues. However, given that correlations with data from Russian North Pole drifting station records are all roughly equal and that they depict similar interannual variability at the regional scale, all of the reanalyses appear suitable for supporting retrievals of ice thickness (provided that appropriate bias corrections can be applied). However, only CFSR, MERRA2, ERA5, and JRA55 will continue to generate output beyond 2019. Plain Language Summary While the thickness of the sea ice that floats atop the Arctic Ocean can be measured using satellite altimeters—instruments that measure the height that something projects above the surface—this assumes that one knows the mass of any snow cover that lies atop the ice. Estimating the overlying snow cover is a formidable task. One way forward is to use estimates of precipitation from a type of weather model known as an atmospheric reanalysis. We look at precipitation from six different reanalyses and find that all of them hold much potential for providing fields of precipitation. |
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