Interannual variability in global soil respiration, 1980-94
Interannual variability in global soil respiration, 1980-94
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DOI：
10.1046/j.1365-2486.2002.00511.x
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发表时间：
2002-08-01
影响因子：
11.6
通讯作者：
Bhagawati, D
中科院分区：
文献类型：
--
作者：
Raich, JW;Potter, CS;Bhagawati, D
我们使用气候驱动的回归模型对 1980 年 1 月至 1994 年 12 月期间每个月陆地表面的土壤二氧化碳排放量进行空间分辨估计，以评估气候年际变化对全球土壤到大气二氧化碳通量的影响。这 15 年期间全球土壤二氧化碳通量年均估计为 80.4（范围 79.3-81.8）Pg C。全球土壤二氧化碳排放量的月度变化与北半球的平均温度周期密切相关。全球范围内，土壤二氧化碳排放量在 2 月份达到最低水平，并在 7 月和 8 月达到峰值。热带和亚热带常绿阔叶林向大气中排放的来自土壤的二氧化碳比任何其他植被类型都多（约占总量的 30%），并且排放量呈半年循环。其他生物群落中的土壤二氧化碳排放表现出与季节性温度循环平行的单一年度循环。估计的全球土壤二氧化碳产量的年际变化远小于植物净碳吸收（即净初级生产力）的变化。因此，土壤似乎可以缓冲大气中的二氧化碳浓度，以应对植物生长中更为显着的季节性和年际差异。在季节性干旱生物群落（稀树草原、丛林和沙漠）内，土壤二氧化碳排放量的年际变化与降水量的年际差异显着相关。然而，在全球范围内，年土壤二氧化碳通量与年平均温度相关，斜率为每摄氏度 3.3 Pg C y(-1)。尽管降水分布影响土壤二氧化碳排放的季节和空间格局，但全球变暖可能会刺激土壤二氧化碳排放。
We used a climate-driven regression model to develop spatially resolved estimates of soil-CO2 emissions from the terrestrial land surface for each month from January 1980 to December 1994, to evaluate the effects of interannual variations in climate on global soil-to-atmosphere CO2 fluxes. The mean annual global soil-CO2 flux over this 15-y period was estimated to be 80.4 (range 79.3-81.8) Pg C. Monthly variations in global soil-CO2 emissions followed closely the mean temperature cycle of the Northern Hemisphere. Globally, soil-CO2 emissions reached their minima in February and peaked in July and August. Tropical and subtropical evergreen broad-leaved forests contributed more soil-derived CO2 to the atmosphere than did any other vegetation type (similar to30% of the total) and exhibited a biannual cycle in their emissions. Soil-CO2 emissions in other biomes exhibited a single annual cycle that paralleled the seasonal temperature cycle. Interannual variability in estimated global soil-CO2 production is substantially less than is variability in net carbon uptake by plants (i.e., net primary productivity). Thus, soils appear to buffer atmospheric CO2 concentrations against far more dramatic seasonal and interannual differences in plant growth. Within seasonally dry biomes (savannas, bushlands and deserts), interannual variability in soil-CO2 emissions correlated significantly with interannual differences in precipitation. At the global scale, however, annual soil-CO2 fluxes correlated with mean annual temperature, with a slope of 3.3 Pg C y(-1) per degreesC. Although the distribution of precipitation influences seasonal and spatial patterns of soil-CO2 emissions, global warming is likely to stimulate CO2 emissions from soils.