CAJ | 학술논문

为研究中国植被生态系统蒸散比（evaporative fraction，EF）的时空分布及其与气候因素之间的关系，该文利用遥感数据、气象数据以及地面涡度相关站点观测数据，通过植被指数－地表温度所围成的特征空间，估算且验证了了2003－2009年间中国植被生态系统逐月EF，并对月均EF的时空分布及其对气候因素的响应进行了分析。结果发现：中国植被生态系统月均EF呈现出明显的季节变化特征，四季中，华南地区月均EF普遍高于中国其他地区。春季开始后，长江以南以及四川盆地月均EF开始升高，进入夏季后月均EF高值区向北扩张至华北、东北等地。中国植被生态系统月均EF与气候因素之间的关系存在季节差异。春、秋两季，月均EF与太阳辐射月总量、月均温及月降水量均有显著关系（P＜0.01）；冬季，温度则成为植被月均EF空间分布的主要影响因子（P＜0.01）；夏季，气候因素则与植被月均EF空间分布无显著关系（P＞0.05）。中国植被生态系统月均EF的季节变化与气候因素之间的关系也有明显的地区差异。中国北方、内陆地区月均EF季节变化对降水量更为敏感；而中国南方、沿海地区月均EF则对温度和太阳辐射更为敏感。中国各典型植被中，农田月均EF对降水量、温度及太阳辐射的敏感度高于其他植被类型（P＜0.05）；多数森林植被EF的季节变化受到降水量的影响小于农田、草地和灌木（P＜0.05）；森林植被中，太阳辐射则较易影响阔叶植被月均EF的季节变化，而相较于针叶林，阔叶林月均EF对温度的敏感度较高（P＜0.05）。该研究结果为中国地表水分状况评估提供科学依据。
위연구중국식피생태계통증산비（evaporative fraction，EF）적시공분포급기여기후인소지간적관계，해문이용요감수거、기상수거이급지면와도상관참점관측수거，통과식피지수－지표온도소위성적특정공간，고산차험증료료2003－2009년간중국식피생태계통축월EF，병대월균EF적시공분포급기대기후인소적향응진행료분석。결과발현：중국식피생태계통월균EF정현출명현적계절변화특정，사계중，화남지구월균EF보편고우중국기타지구。춘계개시후，장강이남이급사천분지월균EF개시승고，진입하계후월균EF고치구향북확장지화북、동북등지。중국식피생태계통월균EF여기후인소지간적관계존재계절차이。춘、추량계，월균EF여태양복사월총량、월균온급월강수량균유현저관계（P＜0.01）；동계，온도칙성위식피월균EF공간분포적주요영향인자（P＜0.01）；하계，기후인소칙여식피월균EF공간분포무현저관계（P＞0.05）。중국식피생태계통월균EF적계절변화여기후인소지간적관계야유명현적지구차이。중국북방、내륙지구월균EF계절변화대강수량경위민감；이중국남방、연해지구월균EF칙대온도화태양복사경위민감。중국각전형식피중，농전월균EF대강수량、온도급태양복사적민감도고우기타식피류형（P＜0.05）；다수삼림식피EF적계절변화수도강수량적영향소우농전、초지화관목（P＜0.05）；삼림식피중，태양복사칙교역영향활협식피월균EF적계절변화，이상교우침협림，활협림월균EF대온도적민감도교고（P＜0.05）。해연구결과위중국지표수분상황평고제공과학의거。
Evaporative fraction (EF) is an important parameter to estimate evapotranspiration (ET) for regional ecosystem, and also an indicator to evaluate the moisture status of the terrestrial ecosystem. Based on the climate data in China and moderate-resolution imaging spectroradiometer (MODIS) products such as MOD11B3, MOD13A3 and MOD12, this manuscript focused on the monthly mean EF estimation using the Priestley-Taylor model and EF validation using the ground-based eddy measurement data, analyzed the spatio-temporal patterns of monthly mean EF and evaluated its responses to the climate factors in the vegetated region in China, in order to obtain the seasonal change characteristics of EF and its sensitivity to climate. Results showed that monthly mean EF dynamics in the vegetation ecosystems had significant seasonal change characteristics. During the whole year, vegetation ecosystem in South China had a higher value than those in other regions in China. In spring, monthly mean EF increased in the south of Yangtze River and Sichuan Basin. And then the regions with high EF value expanded to the North China Plain and the Northeast China in summer. In autumn, the regions with high EF value shrank, and the distribution of monthly mean EF was similar to that in spring. The correlations between the spatial distribution of EF and climate factors showed seasonal variability. In spring and autumn, the EF was significantly correlated(P<0.01) with monthly total solar radiation, monthly mean temperature and monthly precipitation. In winter, monthly mean temperature was the sole factor significantly affecting(P<0.01) the EF in vegetation ecosystem in China. Contrary to these, there were no significant correlations between EF and climate factors in summer. The reason was the distinguishing relationships between monthly mean EF and climatic factors. Regional variability was also found in the sensitivity of seasonal EF to the climate. The higher sensitivity to monthly precipitation was found in the northern and inland regions compared to that in the southern and coastal regions. On the contrary, vegetation ecosystem in the southern and coastal regions showed higher sensitivity to monthly mean temperature and monthly solar radiation. This was accordant with the differences of the moisture conditions between northern and southern ecosystems. In Southwest China, the negative relationship between monthly mean EF and monthly mean temperature showed the drought in the hot season was controlled by the southwest monsoon in this region. On the Qinghai-Tibet Plateau, the sensitivity of monthly mean EF to climate was lower than that in other regions. Monthly mean EF of deciduous broadleaf forest, shrub land and grassland had high seasonal variability, while the seasonal variability on monthly mean EF of evergreen broadleaf forest was relatively insignificant. The relationships between EF and climatic factors for each vegetation type showed that monthly mean EF of cropland was more highly related to monthly precipitation, monthly mean temperature and monthly solar radiation than those of other vegetation types. Compared to cropland, monthly mean EF of forest showed less sensitivity to monthly precipitation. Among various forest types, monthly mean EF of mixed forest and evergreen broadleaf forest had the highest sensitivity to monthly solar radiation, followed by deciduous broadleaf forest, deciduous conifer forest and evergreen conifer forest, suggesting that the broadleaf forest had higher sensitivity to monthly solar radiation. Similar to the sensitivity to monthly solar radiation, monthly mean EF of broadleaf forest had a higher sensitivity to monthly mean temperature than that of conifer forest.