Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin

Trent W. Biggs, Christopher A Scott, Anju Gaur, Jean Philippe Venot, Thomas Chase, Eungul Lee

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Changes in both land cover and the atmosphere have impacted the heat fluxes of south Asia in ways that may have altered the timing and magnitude of the monsoon. Century-long budgets of water and energy in the Krishna Basin (258,948 km2) in southern India demonstrate that irrigation impacted the sensible heat flux of the land surface (H) as much as or more than did the atmospheric brown cloud (ABC) over 1960-2005. Annual discharge of the Krishna River fell from 226 mm during pre-irrigation land cover (1901-1960) to 64 mm by 1990-2005, when 14-20% of the basin area was irrigated. Over the same period, annual evaporation increased by 166 ± 32 mm (+28%) causing H to decrease by 12.7 ± 2 W m-2 (-18%) compared to a decrease of 11.2 ± 1.8 W m-2 caused by the atmospheric brown cloud (ABC). The rate of change in H during irrigation expansion (1960-1990) was between -3.4 and -5.0 W m-2 per decade (da-1) due to irrigation expansion and -1.8 to -2.3 W m-2 da-1 due to the ABC. The trend in H caused by irrigation was negligible over 1990-2005 as irrigated area and evaporation stabilized. Previous work using the Parallel Climate Model estimated that the ABC decreased the latent heat flux by 2.4 W m-2; this decrease was more than offset by irrigation, resulting in a net increase in the latent heat flux of 12.9 W m-2. The maximum surface air temperature (Tmax) either decreased or remained the same in areas experiencing irrigation expansion but increased in a majority of unirrigated areas during the post-monsoon season. The results provide observational evidence that irrigation changed both the basin-scale sensible heat flux and surface air temperatures.

Original languageEnglish (US)
Article numberW12415
JournalWater Resources Research
Volume44
Issue number12
DOIs
StatePublished - Dec 2008

Fingerprint

heat flux
water budget
surface temperature
river basin
irrigation
aerosol
latent heat flux
sensible heat flux
land cover
monsoon
air temperature
evaporation
basin
land surface
climate modeling
atmosphere
river
energy

ASJC Scopus subject areas

  • Water Science and Technology

Cite this

Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin. / Biggs, Trent W.; Scott, Christopher A; Gaur, Anju; Venot, Jean Philippe; Chase, Thomas; Lee, Eungul.

In: Water Resources Research, Vol. 44, No. 12, W12415, 12.2008.

Research output: Contribution to journalArticle

Biggs, Trent W. ; Scott, Christopher A ; Gaur, Anju ; Venot, Jean Philippe ; Chase, Thomas ; Lee, Eungul. / Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin. In: Water Resources Research. 2008 ; Vol. 44, No. 12.
@article{8ea6481e8f0a4350bdba74381abfd66a,
title = "Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin",
abstract = "Changes in both land cover and the atmosphere have impacted the heat fluxes of south Asia in ways that may have altered the timing and magnitude of the monsoon. Century-long budgets of water and energy in the Krishna Basin (258,948 km2) in southern India demonstrate that irrigation impacted the sensible heat flux of the land surface (H) as much as or more than did the atmospheric brown cloud (ABC) over 1960-2005. Annual discharge of the Krishna River fell from 226 mm during pre-irrigation land cover (1901-1960) to 64 mm by 1990-2005, when 14-20{\%} of the basin area was irrigated. Over the same period, annual evaporation increased by 166 ± 32 mm (+28{\%}) causing H to decrease by 12.7 ± 2 W m-2 (-18{\%}) compared to a decrease of 11.2 ± 1.8 W m-2 caused by the atmospheric brown cloud (ABC). The rate of change in H during irrigation expansion (1960-1990) was between -3.4 and -5.0 W m-2 per decade (da-1) due to irrigation expansion and -1.8 to -2.3 W m-2 da-1 due to the ABC. The trend in H caused by irrigation was negligible over 1990-2005 as irrigated area and evaporation stabilized. Previous work using the Parallel Climate Model estimated that the ABC decreased the latent heat flux by 2.4 W m-2; this decrease was more than offset by irrigation, resulting in a net increase in the latent heat flux of 12.9 W m-2. The maximum surface air temperature (Tmax) either decreased or remained the same in areas experiencing irrigation expansion but increased in a majority of unirrigated areas during the post-monsoon season. The results provide observational evidence that irrigation changed both the basin-scale sensible heat flux and surface air temperatures.",
author = "Biggs, {Trent W.} and Scott, {Christopher A} and Anju Gaur and Venot, {Jean Philippe} and Thomas Chase and Eungul Lee",
year = "2008",
month = "12",
doi = "10.1029/2008WR006847",
language = "English (US)",
volume = "44",
journal = "Water Resources Research",
issn = "0043-1397",
publisher = "American Geophysical Union",
number = "12",

}

TY - JOUR

T1 - Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin

AU - Biggs, Trent W.

AU - Scott, Christopher A

AU - Gaur, Anju

AU - Venot, Jean Philippe

AU - Chase, Thomas

AU - Lee, Eungul

PY - 2008/12

Y1 - 2008/12

N2 - Changes in both land cover and the atmosphere have impacted the heat fluxes of south Asia in ways that may have altered the timing and magnitude of the monsoon. Century-long budgets of water and energy in the Krishna Basin (258,948 km2) in southern India demonstrate that irrigation impacted the sensible heat flux of the land surface (H) as much as or more than did the atmospheric brown cloud (ABC) over 1960-2005. Annual discharge of the Krishna River fell from 226 mm during pre-irrigation land cover (1901-1960) to 64 mm by 1990-2005, when 14-20% of the basin area was irrigated. Over the same period, annual evaporation increased by 166 ± 32 mm (+28%) causing H to decrease by 12.7 ± 2 W m-2 (-18%) compared to a decrease of 11.2 ± 1.8 W m-2 caused by the atmospheric brown cloud (ABC). The rate of change in H during irrigation expansion (1960-1990) was between -3.4 and -5.0 W m-2 per decade (da-1) due to irrigation expansion and -1.8 to -2.3 W m-2 da-1 due to the ABC. The trend in H caused by irrigation was negligible over 1990-2005 as irrigated area and evaporation stabilized. Previous work using the Parallel Climate Model estimated that the ABC decreased the latent heat flux by 2.4 W m-2; this decrease was more than offset by irrigation, resulting in a net increase in the latent heat flux of 12.9 W m-2. The maximum surface air temperature (Tmax) either decreased or remained the same in areas experiencing irrigation expansion but increased in a majority of unirrigated areas during the post-monsoon season. The results provide observational evidence that irrigation changed both the basin-scale sensible heat flux and surface air temperatures.

AB - Changes in both land cover and the atmosphere have impacted the heat fluxes of south Asia in ways that may have altered the timing and magnitude of the monsoon. Century-long budgets of water and energy in the Krishna Basin (258,948 km2) in southern India demonstrate that irrigation impacted the sensible heat flux of the land surface (H) as much as or more than did the atmospheric brown cloud (ABC) over 1960-2005. Annual discharge of the Krishna River fell from 226 mm during pre-irrigation land cover (1901-1960) to 64 mm by 1990-2005, when 14-20% of the basin area was irrigated. Over the same period, annual evaporation increased by 166 ± 32 mm (+28%) causing H to decrease by 12.7 ± 2 W m-2 (-18%) compared to a decrease of 11.2 ± 1.8 W m-2 caused by the atmospheric brown cloud (ABC). The rate of change in H during irrigation expansion (1960-1990) was between -3.4 and -5.0 W m-2 per decade (da-1) due to irrigation expansion and -1.8 to -2.3 W m-2 da-1 due to the ABC. The trend in H caused by irrigation was negligible over 1990-2005 as irrigated area and evaporation stabilized. Previous work using the Parallel Climate Model estimated that the ABC decreased the latent heat flux by 2.4 W m-2; this decrease was more than offset by irrigation, resulting in a net increase in the latent heat flux of 12.9 W m-2. The maximum surface air temperature (Tmax) either decreased or remained the same in areas experiencing irrigation expansion but increased in a majority of unirrigated areas during the post-monsoon season. The results provide observational evidence that irrigation changed both the basin-scale sensible heat flux and surface air temperatures.

UR - http://www.scopus.com/inward/record.url?scp=59749101063&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=59749101063&partnerID=8YFLogxK

U2 - 10.1029/2008WR006847

DO - 10.1029/2008WR006847

M3 - Article

VL - 44

JO - Water Resources Research

JF - Water Resources Research

SN - 0043-1397

IS - 12

M1 - W12415

ER -