Uncertainties in ocean latent heat flux variations over recent decades in satellite-based estimates and reduced observation reanalyses

Franklin R. Robertson*, Jason B. Roberts, Michael G. Bosilovich, Abderrahim Bentamy, Carol Anne Clayson, Karsten Fennig, Marc Schröder, Hiroyuki Tomita, Gilbert P. Compo, M. Gutenstein, Hans Hersbach, Chiaki Kobayashi, Lucrezia Ricciardulli, Prashant Sardeshmukh, Laura C. Slivinski

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

7 Citations (Scopus)

Abstract

Four state-of-the-art satellite-based estimates of ocean surface latent heat fluxes (LHFs) extending over three decades are analyzed, focusing on the interannual variability and trends of near-global averages and regional patterns. Detailed intercomparisons are made with other datasets including 1) reduced observation reanalyses (RedObs) whose exclusion of satellite data renders them an important independent diagnostic tool; 2) a moisture budget residual LHF estimate using reanalysis moisture transport, atmospheric storage, and satellite precipitation; 3) the ECMWF Reanalysis 5 (ERA5); 4) Remote Sensing Systems (RSS) single-sensor passive microwave and scatterometer wind speed retrievals; and 5) several sea surface temperature (SST) datasets. Large disparities remain in near-global satellite LHF trends and their regional expression over the 1990–2010 period, during which time the interdecadal Pacific oscillation changed sign. The budget residual diagnostics support the smaller RedObs LHF trends. The satellites, ERA5, and RedObs are reasonably consistent in identifying contributions by the 10-m wind speed variations to the LHF trend patterns. However, contributions by the near-surface vertical humidity gradient from satellites and ERA5 trend upward in time with respect to the RedObs ensemble and show less agreement in trend patterns. Problems with wind speed retrievals from Special Sensor Microwave Imager/Sounder satellite sensors, excessive upward trends in trends in Optimal Interpolation Sea Surface Temperature (OISST AVHRR-Only) data used in most satellite LHF estimates, and uncertainties associated with poor satellite coverage before the mid-1990s are noted. Possibly erroneous trends are also identified in ERA5 LHF associated with the onset of scatterometer wind data assimilation in the early 1990s.

Original languageEnglish
Pages (from-to)8415-8437
Number of pages23
JournalJournal of climate
Volume33
Issue number19
DOIs
Publication statusPublished - 1 Oct 2020
Externally publishedYes

Keywords

  • ITC-CV

Fingerprint

Dive into the research topics of 'Uncertainties in ocean latent heat flux variations over recent decades in satellite-based estimates and reduced observation reanalyses'. Together they form a unique fingerprint.

Cite this