Effects of Anthropogenic Aerosol and Greenhouse Gas Changes on West African and Indian Monsoon Precipitation.
Abstract
West Africa underwent an extended drought between 1960s to 1980s and experienced a limited precipitation recovery afterwards. Meanwhile, India underwent a long-term summer drying trend, from the 1950s to the 2000s. These decadal-to-multidecadal changes in climate are associated with changes in anthropogenic forcing and internal climate variability. We analyse outputs of CMIP6 Detection and Attribution MIP simulations to assess the relative importance of anthropogenic aerosols and greenhouse gases (GHG) in Sahel and Indian precipitation trends over the course of the 20th and early 21st centuries. We show that changing anthropogenic aerosol emissions is one of the drivers of the Sahelian drought through changes in temperature gradients and a shifting of the monsoon circulation southwards, while the recovery is mostly associated with the decrease in European anthropogenic aerosol emissions and increased global emissions of GHG. Over Asia, increased aerosol emissions are associated with a decrease in precipitation by impacting the monsoon circulation, while the increase in GHG concentrations is associated with an increase in moisture advection inland. We use the CMIP6 multi-model ensemble to quantify and document model differences in effects of anthropogenic aerosols and GHG emissions over West Africa and India. Finally, we also assess how external forcing could shape changes in future precipitation change over the 21st century.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMA229.0005M
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 3319 General circulation;
- ATMOSPHERIC PROCESSES;
- 3337 Global climate models;
- ATMOSPHERIC PROCESSES;
- 3373 Tropical dynamics;
- ATMOSPHERIC PROCESSES