Effect of spring burning on the surface energy balance in a tallgrass prairie
Effect of spring burning on the surface energy balance in a tallgrass prairie
复制标题
DOI：
10.1016/s0168-1923(99)00034-9
复制
发表时间：
1999-09-28
影响因子：
6.2
通讯作者：
Ham, JM
中科院分区：
文献类型：
--
作者：
Bremer, DJ;Ham, JM
春季焚烧高草草原的死生物量是一种常见的做法，可能会影响热量和水蒸气从景观传输。采用波文比法对美国堪萨斯州曼哈顿附近的火烧（B）和未火烧（UB）草原的地表能量平衡和蒸散量（ET）进行了测定。数据收集日期为1997年DOY 109-258日，在DOY 107的B现场发生火灾后。在生长季节的早期，水蒸气输送的电导率和表面电导率的差异（g（s），即，覆盖效应）引起B和UB站点之间能量通量的巨大变化。在烧伤后44天内（DOY 109-152），与UB部位相比，B部位的平均血药浓度低43%。因此，可用能量（净辐射减去土壤热通量）的B比UB网站高8.6%。在此期间，B场地的g（s）比现场高出三倍以上，这是通过火灾去除死生物质的结果。在同一时期，白天Bowen比平均为0.79（B站点）和2.89（UB站点），ET率为2.97 mm/天（B站点）和1.40 mm/天（UB站点）。到DOY 152，冠层生长缓和了不同地点之间的光合作用和可用能量的差异。然而，在DOY 152和181之间，B位点的g（s）和ET仍然较高。绿色叶面积指数在B站点上平均高71%，并且是这种季节中期效应的主要原因（即，蒸腾作用的差异）。到DOY 182，燃烧对能量通量的影响可以忽略不计。在150天期间的累积估计ET为503毫米的B网站和408毫米的UB网站，因此，燃烧增加季节性ET的23.3%。结果表明，土地管理或影响枯落物，芦苇，或绿色叶面积的环境因素将有很大的影响，草地的水和能量平衡。(C)1999 Elsevier Science B. V.保留所有权利。
Spring burning of dead biomass in tallgrass prairie is a common practice that may influence heat and water vapor transport from the landscape. Bowen ratio methods were used to measure the surface energy balances and evapotranspiration (ET) from burned (B) and unburned (UB) prairie near Manhattan, KS, USA. Data were collected from day of year (DOY) 109-258, 1997 following fire on the B site on DOY 107. Early in the growing season, differences in albedo and surface conductance to water vapor transport (g(s), i.e., mulch effect) caused large variations in energy fluxes between B and UB sites. During a 44-day period immediately after the burn (DOY 109-152), albedo averaged 43% lower on the B compared with the UB site. Consequently, available energy (net radiation minus soil heat flux) was 8.6% higher on the B than on the UB site. The g(s) during that time was over three times higher on the B site, a result of dead biomass removal by fire. During the same period, the daytime Bowen ratios averaged 0.79 on the B site and 2.89 on the UB site, with ET rates of 2.97 mm per day (B site) and 1.40 mm per day (UB site). By DOY 152, canopy growth had moderated differences in albedo and available energy between sites. However, g(s) and ET remained higher on the B site between DOY 152 and 181. Green leaf area index averaged 71% higher on the B site, and was the primary cause for this mid-season effect (i.e., differences in transpiration). By DOY 182, the effects of the burn on energy fluxes were negligible. Cumulative estimates of ET during the 150-day period were 503 mm on the B site and 408 mm on the UB site, thus, burning increased seasonal ET by 23.3%. Results suggest that land management or environmental factors that affect dead litter, albedo, or green leaf area will have strong impacts on the water and energy balances of a grassland. (C) 1999 Elsevier Science B.V. All rights reserved.