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 = "19 jan. 2021"