Assessment of Uncertainties in Recent Changes in the South American Low-Level Jet Based on Various Reanalyses
Abstract
The South American low-level jet (SALLJ) is one of the key components of the South American Monsoon System. The SALLJ transports large amounts of moisture to the subtropics, influencing the development of deep convection and heavy precipitation over southeastern South America. Previous studies have analyzed the jet using reanalysis data due to the lack of available upper-air observations over this region. The purpose of the current study is to quantify uncertainties in the climatology, variability, and changes in the SALLJ based on various reanalyses for the period 1979-2015. This is important because there are significant differences among reanalysis datasets due to variations in their data quality control, data assimilation systems, and model physics. The datasets used in this analysis are: (1) Climate Forecast System Reanalysis, (2) ERA-Interim, (3) the Japanese 55-year reanalysis, (4) the Second Modern Era Retrospective-analysis for Research and Applications (MERRA-2). Finally, significant changes in the SALLJ are discussed in relation to substantial warming over South America in recent decades and changes in the monsoon.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.A21F2215M
- Keywords:
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- 1622 Earth system modeling;
- GLOBAL CHANGE;
- 1622 Earth system modeling;
- GLOBAL CHANGE;
- 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDS;
- 4513 Decadal ocean variability;
- OCEANOGRAPHY: PHYSICAL