Seasonal variation of energy fluxes in caatinga areas preserved and degraded in Northeast Brazil

Abstract

A maior parte da região semiárida brasileira é composta pelo bioma Caatinga, com extensão de 734.478 km² que abrange cerca de 9% do território nacional e representando quase e 76% do semiárido caracterizado pelo déficit hídrico. A Caatinga é considerada um bioma bastante heterogêneo, sucetível às alterações antrópicas, porém sua dinâmica dos fluxos turbulentos entre o ecossistema e a atmosfera ainda são pouco estudadas. Os fluxos turbulentos são estimados pela técnica de eddycovariance a partir de cálculos estatísticos entre a covariância da velocidade vertical do vento e a razão de mistura do gás. O objetivo principal deste trabalho foi analisar a variação durante o ano de 2013 das componentes do balanço de energia, de duas áreas de Caatinga preservada e degradada, pertencentes ao Instituto Nacional do Semiárido (INSA), município de Campina Grande – CG, onde foram instaladas duas torres micrometeorológicas. A partir das componentes do balanço de energia fez-se o estudo do fechamento deste e verificou-se que o mesmo não ocorreu, devido àsubestimativa dos fluxos turbulentos. Normal 0 false false false PT-BR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:PT-BR;} A B S T R A C T Most of the Brazilian semiarid region is composed of the Caatinga biome, characterized by drought. The Caatinga biome is considered a very heterogeneous, susceptible to anthropogenic changes, however its dynamics of turbulent flows between the ecosystem and the atmosphere are still poorly studied. The main objective of this study was to analyze the annual variation of the daily cycle of energy balance components, as well as the closure of the energy balance in areas of Caatinga preserved and degraded during the year 2013 in city of Campina Grande - PB. Turbulent fluxes are estimated by eddy covariance technique from statistical calculations of the covariance of the vertical wind speed and the gas mixture ratio. There was an increase of latent heat flux during the rainy season and decrease to the net radiation, sensible heat flux and soil heat flux and behavior contrary to the dry season. Also, it was possible to see greater variation of balance components in the preserved to degraded area. From the energy balance components it made up the study of the closing of this and it was found that this did not occur due to underestimation of turbulent flows. Keywords: turbulent fluxes; energy balance; preserved and degraded Caatinga. Normal 0 21 false false false PT-BR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;}