Abstract
Pre-monsoon dust aerosols over Indian regions are closely linked to the monsoon dynamics and Indian summer monsoon rainfall. Past observational studies have shown a decline in dust loading over the Indian landmass potentially caused by changing rainfall patterns over the desert regions. Such changes are expected to have a far-reaching impact on regional energy balance and monsoon rainfall. Using a regional climate-chemistry model, RegCM4.5, with an updated land module, we have simulated the long-term (2001–2015) changes in dust over the arid and semi-arid dust source regions of the North-Western part of the subcontinent. It is found that the area-averaged dust aerosol optical depth (AOD) over the arid and semi-arid desert regions has declined by 17% since the start of this millennium. The rainfall over these regions exhibits a positive trend of 0.1 mm day−1year−1 and a net increase of >50%. The wet deposition is found to be dominant and ~five-fold larger in magnitude over dry deposition and exhibits total changes of ~79 and 48% in the trends in atmospheric dust. As a response, a significant difference in the surface (11%), top of the atmosphere radiative forcing (7%), and widespread atmospheric cooling are observed in the short wave domain of radiation spectrum over the Northern part of the Indian landmass. Such quantification and long-term change studies are necessary for understanding regional climate change and the water cycle.
Highlights
Mineral dust is one of the most important sources for aerosol mass in the atmosphere [1]
This section explains the simulated spatial pattern and trends of dust aerosol optical depth (AOD), rainfall, burden, and radiative parameters related to dust
AOD, rainfall, In the second part, we calculate the long-term area-averaged temporal of these tracer burden, and radiative parameters related to dust
Summary
Mineral dust (or dust) is one of the most important sources for aerosol mass in the atmosphere [1]. The primary sources of dust over the Indian landmass are the arid and semi-arid regions (mostly North-Western and adjacent parts of India) and long-range transport from Middle-West Asia and North Africa by the westerly winds [11,12,13,14,15,16] It peaks during April/May and declines thereafter due to the arrival of monsoon and enhanced wet deposition [13,15]. The inadequate representation of various processes, coarse spatial resolution of soil data, and meteorological fields in typical global climate models (GCMs) make it difficult to study dust and its feedback at regional scales. The changes (quantification) in short and longwave radiation at the surface, atmosphere, and top of the atmosphere during the period are elucidated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
