Impact of air pollution on the south asian monsoon
Download
1 / 25

Impact of Air Pollution on the South Asian Monsoon - PowerPoint PPT Presentation


  • 110 Views
  • Uploaded on
  • Presentation posted in: General

Impact of Air Pollution on the South Asian Monsoon. A Paper Review Siv Balachandran 04/26/07. Overview. Motivation South Asian Monsoon Aerosols/Haze in South Asia Impact of Air Pollution on Monsoon UNEP 2002 Ramanathan et al 2005 Chung et al 2006 Conclusions. Motivation. India

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha

Download Presentation

Impact of Air Pollution on the South Asian Monsoon

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Impact of Air Pollution on the South Asian Monsoon

A Paper Review

Siv Balachandran

04/26/07


Overview

  • Motivation

  • South Asian Monsoon

  • Aerosols/Haze in South Asia

  • Impact of Air Pollution on Monsoon

    • UNEP 2002

    • Ramanathan et al 2005

    • Chung et al 2006

  • Conclusions


MODIS Satellite picture from wikepedia


Motivation

  • India

    • 1 Billion and growing

    • Emissions are increasing

  • South Asia

    • Also growing

    • Monsoon = survival

    • Health Impacts

  • Globally

    • Transport of pollution

    • Climate Change Impacts

UNEP 2002


2 monsoons

June - September: SW

December - April: NE

SW monsoon predominant for most of South Asia

1856 - 1997

30 El Nino, with 10 drought

16 La Nina, with 7 flood

Studies suggest weakening due to global warming

Anthropogenic aerosol load

October to June

Peaks in Feb/March

May is transition period

Winds change from NE to SW

April/May - warmest

The South Asian Monsoon


UNEP 2002


Aerosol/Haze Composition

  • Natural vs. Anthropogenic

  • INDOEX

    • Brown Cloud in dry winter months due to aerosols

  • Monsoons wash out aerosols

UNEP 2002


Aerosol Composition

Carrico 2003


UNEP 2002


8 major impacts

  • Aerosol forcing

  • Dimming

  • Reduction in surface evaporation

  • Surface cooling

  • Weakening of latitudinal SST Gradients

  • Stabilization of the troposphere

  • Decrease in monsoon rainfall

  • ABC induced droughts

Ramanathan et al 2005


Aerosol Impact on Climate

  • Direct Effects

    • Changes to Radiative Forcing

  • Indirect Effects

    • Cloud albedo

    • Cloud lifetime

  • Semi-Direct

    • Reduction in cloud cover and albedo due to aerosol induced increase in solar heating


Papers Reviewed

  • Ramanathan et al 2005

    • Coupled ocean - atmospheric GCM

    • Cases

      • GHGs+SO4_2050 (business as usual)

      • ABC_1998 (GHGs, SO4, ABC @1998)

      • ABC_2050 (increases in GHGs and SO4 and extrapolates ABC forcing)

      • ABC_2050_1 (GHGs and SO4 held at 1998)

  • Chung et al 2006

    • CCM3


Aerosol Forcing

Ramanathan et al 2005


Radiative Forcing Impacts

UNEP 2002


Dimming

Ramanathan et al 2005


Impact of SST Changes

  • Atmospheric heating  Surface Cooling

  • Indian Ocean SST changes

    • NIO cools

    • Equatorial IO warms

  • SST gradient affects pressure gradient

  • Pressure gradient affects circulation

  • Net effect = monsoon is disturbed


Stabilization of the Troposphere

  • In the first 5km: dT/dz = -5 to -6 K/km

  • Unstable to moist convection

  • Instability coupled with low-level moisture convergence  deep convection

  • Aerosols/haze confined to ~ 4km

    • Heating of aerosol-loaded inhibits instability via differential warming of the atmosphere


Pressure Gradients

  • Surface pressure late spring/early summer

    • NIO is warmer

    • SOE > 1015 mb

    • NIO < 1005 mb

  • Cross equatorial pressure gradient drives moisture from SIO to South Asia

  • Cooling of NIO causes SST gradient that reverses pressure gradient

  • Mid to upper troposphere

    • Cooler NIO  less deep convection in NIO

    • N to S circulation is disrupted


Circulation Impacts

Ramanathan et al 2005


Rainfall Trends

Ramanathan et al 2005


Chung et al 2006


Chung et al 2006


Increased Droughts

Ramanathan et al 2005


Conclusions

  • Aerosol/haze impacts

    • Direct and indirect effects

    • SST changes affect circulation

    • Droughts

    • Transport of pollution

  • More than 1 billion people directly dependent on South Asian monsoon

    • Impacts to agriculture/health/global


ad
  • Login