Contrasting Phase Changes of Precipitation Annual Cycle Between Land and Ocean Under Global Warming. Issue 20 (22nd October 2020)

• Record Type: Journal Article
• Authors: Song, Fengfei; Lu, Jian; Leung, L. Ruby; Liu, Fukai
• Is Part Of: Geophysical research letters. Volume 47:Issue 20(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-22
• Subjects: global warming -- tropical rainfall -- annual cycle -- phase changes -- land‐sea contrast; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL090327
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We report a land‐ocean contrast in the phase change of precipitation annual cycle in multimodel ensemble simulations as climate warms, with a robust delay over land (0–40°N/S) versus an advance (0–40°N/S) or no clear (0–25°N/S) phase changes over ocean. The robust delay over land is caused by the increased effective atmospheric heat capacity C A . Over ocean, the increased C A favors a phase delay, while the land‐ocean precipitation contrast during the peak rainy season favors a phase advance. The latter overwhelms the former and causes a seasonal advance over 0–40°N/S, while the two factors cancel out and result in no phase changes over 0–25°N/S. Under the atmospheric energetic constraint, the land‐ocean precipitation contrast in the peak rainy season is related to their opposite amplitude changes of surface temperature annual cycle: Seasonally different wind changes enhance the amplitude over ocean, while increased C A and surface cooling feedback reduce the amplitude over land. Plain Language Summary: The seasonal monsoon rainfall provides water resources for ~40% of the world population, but it has been a longstanding challenge to predict the arrival timing of monsoon rain, especially at the regional scale. By separating land from ocean, we revealed that the previous finding of seasonal delay of rainfall under warming mainly occurs over land, where most human activities take place, while ocean shows uncertain phase changes. This contrasting phase behavior between land and ocean is shown to be rooted in the first‐principle physical constraints related to energy and climate feedbacks, thus lending confidence to the differential phase response between land and ocean under climate warming. Key Points: The delay of precipitation annual cycle under warming is more robust over land due to the increased effective atmospheric heat capacity Competition between atmospheric heat capacity increase and summer land‐ocean precipitation contrast causes uncertain phase change over ocean The land‐ocean precipitation contrast in summer is related to the enhanced (reduced) surface temperature annual cycle over ocean (land)