As an essential climate variable (ECV), land surface albedo plays an important role in the Earth surface radiation budget and regional or global climate change. The Tibetan Plateau (TP) is a sensitive environment to climate change, and understanding its albedo seasonal and inter-annual variations is thus important to help capture the climate change rules. In this paper, we analyzed the large-scale spatial patterns, temporal trends, and seasonal variability of land surface albedo overall the TP, based on the moderate resolution imaging spectroradiometer (MODIS) MCD43 albedo products from 2001 to 2019. Specifically, we assessed the correlations between the albedo anomaly and the anomalies of normalized difference vegetation index (NDVI), the fraction of snow cover (snow cover), and land surface temperature (LST). The results show that there are larger albedo variations distributed in the mountainous terrain of the TP. Approximately 10.06% of the land surface is identified to have been influenced by the significant albedo variation from the year 2001 to 2019. The yearly averaged albedo was decreased significantly at a rate of 0.0007 (Sen’s slope) over the TP. Additionally, the yearly average snow cover was decreased at a rate of 0.0756. However, the yearly average NDVI and LST were increased with slopes of 0.0004 and 0.0253 over the TP, respectively. The relative radiative forcing (RRF) caused by the land cover change (LCC) is larger than that caused by gradual albedo variation in steady land cover types. Overall, the RRF due to gradual albedo variation varied from 0.0005 to 0.0170 W/m2, and the RRF due to LCC variation varied from 0.0037 to 0.0243 W/m2 during the years 2001 to 2019. The positive RRF caused by gradual albedo variation or the LCC can strengthen the warming effects in the TP. The impact of the gradual albedo variations occurring in the steady land cover types was very low between 2001 and 2019 because the time series was short, and it therefore cannot be neglected when examining radiative forcing for a long time series regarding climate change.

中文翻译：

---

2001年至2019年青藏高原地表反照率的时空变化

作为重要的气候变量（ECV），地表反照率在地球表面辐射预算以及区域或全球气候变化中起着重要作用。青藏高原（TP）是一个对气候变化敏感的环境，因此了解其反照率的季节和年际变化对于帮助掌握气候变化规则很重要。本文基于2001年至2019年中分辨率成像光谱仪（CDIS）MCD43反照率产品，分析了整个TP地表反照率的大规模空间格局，时间趋势和季节性变化。反照率异常与归一化植被指数（NDVI），积雪比例（雪盖）和地表温度（LST）之间的相关性。结果表明，TP山区地形的反照率变化较大。从2001年到2019年，大约10.06％的土地表面受到显着反照率变化的影响。在TP上，年平均反照率以0.0007（Sen的斜率）的比率显着下降。此外，年平均积雪减少了0.0756。但是，年平均NDVI和LST在TP上分别以0.0004和0.0253的斜率增加。由土地覆盖变化（LCC）引起的相对辐射强迫（RRF）大于在稳定土地覆盖类型中由反照率的逐渐变化引起的相对辐射强迫（RRF）。总体而言，由于反照率的逐渐变化导致的RRF从0.0005到0.0170 W / m2，而由于LCC变化导致的RRF从0.0037到0。2001年至2019年期间的0243 W / m2。由逐渐的反照率变化或LCC引起的正RRF可以增强TP中的变暖作用。由于时间序列短，因此在2001年至2019年之间，在稳定的土地覆盖类型中发生的逐渐反照率变化的影响非常小，因此在研究关于气候变化的长时间序列的辐射强迫时不能忽略不计。