1 引言
2 研究区概况
3 资料与方法
4 积雪监测指标
4.1 积雪频率
4.2 积雪覆盖率
5 结果与分析
5.1 黄河源积雪频率月际分布特征
图3 2001 -2019年黄河源区平均月积雪频率空间分布Fig.3 The spatial distribution of average monthly snow frequency in the Yellow River Source Region from 2001 to 2019 |
5.2 黄河源积雪覆盖率年内变化特征
5.2.1 不同高度带积雪分布及年内变化
5.2.2 不同坡向积雪分布及年内变化
5.3 黄河源积雪覆盖率年际变化特征
5.3.1 全区积雪年际变化
图8 2001 -2019年黄河源区四季及积累期积雪覆盖率年际变化及趋势(a)秋季, (b)冬季, (c)春季, (d)初夏, (e)积累期 Fig.8 The inter-annual variation and trend of snow cover percentage in the Yellow River Source Region during each season and the whole cumulative period from 2001 to 2019.(a) autumn, (b) winter, (c) spring, (d) early summer, (e) the whole accumulative period |
5.3.2 不同高度带积雪年际变化
表1 2001 -2019年黄河源不同高度带积累期及四季积雪覆盖率变化倾向率Table 1 The change tendency rate of snow cover percentage in different altitude zones of the Yellow River Source Region during the cumulative period and each season from 2001 to 2019 |
| 高度带/m | 积雪覆盖率变化倾向率/(%·a-1) | ||||
|---|---|---|---|---|---|
| 秋季 | 冬季 | 春季 | 夏季 | 积累期 | |
| ≤3500 | 0.0984 | -0.0469 | 0.5323* | / | 0.2090 |
| (3500, 4000] | 0.2060 | 0.1346 | 0.7057* | / | 0.3642 |
| (4000, 4500] | 0.3305 | 0.9394* | 0.9174** | 0.0111 | 0.6948* |
| (4500, 5000] | 0.4334 | 1.0554* | 0.9760* | -0.2218 | 0.7464** |
| >5000 | 0.0329 | 0.3130 | 0.5268*** | -0.3278 | 0.2350** |
*、 **、 ***分别表示通过0.10、 0.05、 0.01的显著性检验; /表示无数据 (The ‘*’, ‘**’ and ‘***’ indicate passing significance tests at the 0.10, 0.05 and 0.01 levels, respectively, while ‘/’ indicates that there is no data) |
5.4 黄河源积雪覆盖率与主要气象要素的关系
表2 2001 -2019年黄河源区各高度带积雪积累期及各季气温与降水变化倾向率Table 2 The change tendency rates of temperature and precipitation in each altitude zone of the Yellow River Source Region during the cumulative period of snow and corresponding season from 2001 to 2019 |
| 海拔/m | 气温/(℃·a-1) | 降水/(mm·a-1) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 秋季 | 冬季 | 春季 | 夏季 | 积累期 | 秋季 | 冬季 | 春季 | 夏季 | 积累期 | |
| ≤3500 | 0.0762* | 0.0310 | 0.0075 | / | 0.0292 | 0.2760 | 0.1979 | 1.4268 | / | 1.9008 |
| (3500, 4000] | 0.1003** | 0.0324 | 0.0175 | / | 0.0476** | 0.6765 | 0.2495 | 2.4468*** | / | 3.3729*** |
| (4000, 4500] | 0.0647 | -0.0340 | 0.0072 | 0.0274 | 0.0184 | 1.3208 | 0.2626 | 1.8340** | 0.3428 | 3.7602*** |
*、 **、 ***分别表示通过0.10、 0.05、 0.01的显著性检验; /表示无数据(The ‘*’, ‘**’ and ‘***’ indicate passing significance tests at the 0.10, 0.05 and 0.01 levels, respectively, while the ‘/’ indicates that there is no data) |
表3 2001 -2019年黄河源区各高度带积累期及各季积雪覆盖率与气温和降水的相关系数Table 3 The correlation coefficients between snow cover percentage and temperature, precipitation in each altitude zone of the Yellow River Source Region during the period of snow and corresponding season from 2001 to 2019 |
| 海拔/m | 积雪覆盖率与气温的相关系数 | 积雪覆盖率与降水的相关系数 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 秋季 | 冬季 | 春季 | 夏季 | 积累期 | 秋季 | 冬季 | 春季 | 夏季 | 积累期 | |
| ≤3500 | -0.408* | -0.477** | -0.394* | / | 0.050 | 0.439* | 0.815*** | 0.537** | / | 0.411* |
| (3500~4000] | -0.452* | -0.357 | -0.233 | / | 0.220 | 0.344 | 0.774*** | 0.635*** | / | 0.624*** |
| (4000~4500] | -0.435* | -0.443* | -0.438* | -0.454* | -0.198 | 0.623*** | 0.844*** | 0.466** | -0.064 | 0.792*** |
*、 **、 ***分别表示通过0.10、 0.05、 0.01的显著性检验; /表示无数据(The ‘*’, ‘**’ and ‘***’ indicate passing significance tests at the 0.10, 0.05 and 0.01 levels, respectively, while the ‘/’ indicates that there is no data) |