@Article{OyamaNobr:2004:GCSiSt,
author = "Oyama, Marcos Daysuke and Nobre, Carlos Afonso",
affiliation = "{CPTEC-INPE-Cachoeira Paulista-12630-000-SP-Brasil}",
title = "Climatic consequences of a large-scale desertification in
northeast Brazil: A GCM simulation study",
journal = "Journal of Climate",
year = "2004",
volume = "17",
number = "16",
pages = "3203--3213",
month = "aug.",
keywords = "semi-arid regions, july circulation, biosphere model, global
climate, deforestation, albedo, precipitation, vegetation,
roughness, dynamics.",
abstract = "The climatic impacts of a large-scale desertification in northeast
Brazil (NEB) are assessed by using the Center for Weather
Forecasting and Climate Studies-Center for Ocean-Land-Atmosphere
Studies (CPTEC-COLA) AGCM. Two numerical runs are performed. In
the control run, NEB is covered by its natural vegetation (most of
NEB is covered by a xeromorphic vegetation known as caatinga); in
the desertification run, NEB vegetation is changed to desert (bare
soil). Each run consists of five 1-yr numerical integrations. The
results for NEB wet season (March-May) are analyzed.
Desertification results in hydrological cycle weakening:
precipitation, evapotranspiration, moisture convergence, and
runoff decrease. Surface net radiation decreases and this
reduction is almost evenly divided between sensible and latent
heat flux. Atmospheric diabatic heating decreases and subsidence
anomalies confined at lower atmospheric levels are found. The
climatic impacts result from the cooperative action of feedback
processes related to albedo increase, plant transpiration
suppression, and roughness length decrease. On a larger scale,
desertification leads to precipitation increase in the oceanic
belt close to the northernmost part of NEB (NNEB). In the NEB-NNEB
dipole, the anomalies of vertical motion and atmospheric
circulation are confined to lower atmospheric levels, that is,
850-700 hPa. At these levels, circulation anomalies resemble the
linear baroclinic response of a shallow atmospheric layer (850-700
hPa) to a tropical heat sink placed over NEB at the middle-layer
level. Therefore, NEB climate does show sensitivity to a
vegetation change to desert. The present work shows the
possibility of significant and pronounced climate impacts, on both
regional and large scales, if the environmental degradation in NEB
continues unchecked.",
copyholder = "SID/SCD",
issn = "0894-8755",
language = "en",
targetfile = "Oyama_Climatic consequences.pdf",
urlaccessdate = "04 maio 2024"
}