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Abstract The 1991–2020 climate normals for sea surface temperature (SST) are computed based on the NOAA Daily Optimum Interpolation SST dataset. This is the first time that high‐resolution SST normals with global coverage can be achieved in the satellite SST era. Normals are one of the fundamental parameters in describing and understanding weather and climate and provide decision‐making information to industry, public, and scientific communities. This product suite includes SST mean, standard deviation, count and extreme parameters at daily, monthly, seasonal and annual time scales on 0.25° spatial grids. The main feature of the SST mean state revealed by the normals is that in the Tropics, the Indo‐Pacific Ocean is dominated by the warm pool (SST ≥ 28°C) while the eastern Pacific is characterized by the cold tongue (SST ≤ 24°C); in the midlatitudes, SSTs are in zonal patterns with high meridional gradients. Daily SST standard deviations are generally small (<1.0°C) except in frontal zones (>1.5°C) mostly associated with ocean currents such as the Gulf Stream, Kuroshio and Equatorial Currents. Compared to the 1982–2011 climatology, the 1991–2020 mean SSTs increased over most global areas but obvious cooling is seen in the Southern Ocean, eastern tropical South Pacific Ocean and North Atlantic warming hole. The Indo‐Pacific warm pool (IPWP) is found to have strengthened in both intensity and coverage since 1982–2011. By a count parameter criterion of ≥300 days annually with SST ≥ 28°C, the IPWP coverage increased 33% from 1982–2011 to 1991–2020. The global mean SST of 1991–2020 is warmer than that of 1982–2011, and the warming rate over 1991–2020 doubles that over 1901–2020.
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Effects of Ocean Heat Transport in Tropical Radiative Convective Equilibrium
Abstract A global climate model is run in radiative‐convective equilibrium including a slab ocean with a specified ocean heat transport analogous to what is seen in the tropical Pacific. The insolation is varied to create a range of global mean equilibrium temperatures. These results are compared with experiments that do not include a specified ocean heat transport. The ocean heat transport cools the coldest Sea Surface Temperatures (SSTs) and increases the SST contrast. The warmest SSTs change much less with the addition of ocean heat transport because increased atmospheric transport moves energy away from the warm region. The ocean heat transport also increases the efficiency of cooling by outgoing longwave radiation in the subsiding region, allowing for a cooler global mean SST. At colder global mean temperatures ocean heat transport creates a high‐contrast state in which abundant low clouds play a strong role in maintaining the SST contrast. This high‐contrast state abruptly transitions to a warmer, low‐SST‐contrast state as the climate is warmed by increasing insolation. At warmer temperatures comparable to the current tropics, the low cloud response is less important than longwave emission in maintaining the SST contrast. Although ocean heat transport cools the climate, it does not much affect the sensitivity of the model climate to increasing insolation. Comparison of the model results to ERA5 reanalysis data shows that mechanisms responsible for the SST distribution and energy budget changes in this idealized model are analogous to variability that occurs over the tropical Pacific Ocean.
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- Award ID(s):
- 2124496
- PAR ID:
- 10627624
- Publisher / Repository:
- American Geophysical Union
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Atmospheres
- Volume:
- 130
- Issue:
- 14
- ISSN:
- 2169-897X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1029/2024JD043194
