
Soil moisture in Beijing based on site observation and model simulation
Dao-qing QIN, Yan ZHAO, Hong-rui WANG, Cai-yun DENG, Yong ZHAO
JOURNAL OF NATURAL RESOURCES ›› 2019, Vol. 34 ›› Issue (1) : 191-204.
Soil moisture in Beijing based on site observation and model simulation
It is of great significance to accurately and objectively evaluate the spatial and temporal variation characteristics of soil moisture in studies on the biochemical evolution process of the earth surface. Thus, the combination of model simulation and site observation is necessary to studying water and energy recycling at a regional scale especially. In this paper, based on daily soil surface (0-10 cm) moisture data of 82 monitoring stations in Beijing and GLDAS soil moisture products, the accuracy and consistency of CLDAS was evaluated and the spatio-temporal variability of soil moisture content in Beijing was examined. The root mean square error (RMSE) was used to identify the consistency of CLDAS products and observation values. Specifically, we compared and analyzed the accumulated values of CLDAS products and observation data in 1 day (8∶00, 20∶00), 7 days (8∶00, 20∶00), 15 days (8∶00, 20∶00), 31 days (8∶00, 20∶00), 61 days (8∶00, 20∶00), and 92 days (8∶00, 20∶00). The results showed that: (1) Although the data from CLDAS products were generally slightly higher than the measured data, CLDAS products and site observation data show a good consistency that RMSE in various countries was almost around 10; (2) CLDAS products could reflect the distribution characteristics of soil moisture in Beijing when the temperature was higher than 0 ℃, while there existed a bias in GLDAS products when the temperature was lower than 0 ℃; (3) Based on drought identification based on soil moisture data, we found that the drought area in Beijing was gradually expanding and one extreme drought center was spreading from Changping (soil relative moisture content < 30%) to other districts. Meanwhile, the other area with high soil relative humidity (soil relative moisture content > 50%), centered in Shunyi District, gradually decreased at a spatial scale; (4) In terms of temporal scale, soil moisture in Beijing gradually decreased with the decrease of precipitation that soil humidity at 20∶00 was all higher than that at 8∶00 in the same day (MEobs >0). When the temperature was lower than 0 ℃, soil humidity at 20∶00 and 8∶00 became significantly different. These conclusions would help us make effective use of GLDAS products in soil moisture related studies and would help us know the spatial and temporal variability of soil moisture content in Beijing.
soil moisture / CLDAS / site observation / model simulation / Beijing {{custom_keyword}} /
Fig. 2 The comparison of CLDAS products with observation data day by day图2 研究时间内CLDAS产品估计与实测累日对比 |
Fig. 3 The comparison of CLDAS products with observation data of October图3 10月份CLDAS产品估计与实测累日对比 |
Fig. 4 The comparison of CLDAS products with observation data of November图4 11月份CLDAS产品估计与实测累日对比 |
Fig. 5 The comparison of CLDAS products with observation data of December图5 12月份CLDAS产品估计与实测累日对比 |
Table 1 The average error of soil moisture at 20 o'clock and 8 o'clock in each district表1 各区县站点当日20∶00与8∶00土壤湿度平均误差比较 |
区县 | 实测 | 10月 | 0 ℃之前 | 0 ℃之后 |
---|---|---|---|---|
朝阳 | 0.10 | 0.15 | 0.14 | -6.18 |
丰台 | -0.07 | 0.50 | 0.45 | -6.70 |
海淀 | 0.09 | 0.29 | 0.24 | -6.38 |
通州 | 0.13 | 0.43 | 0.31 | -7.33 |
大兴 | 0.07 | 0.40 | 0.01 | -8.62 |
顺义 | 0.06 | 0.31 | 0.16 | -6.83 |
房山 | 0.06 | 0.38 | 0.19 | -7.77 |
门头沟 | 0 | 0.41 | -0.12 | -6.89 |
昌平 | 0.06 | 0.32 | 0.23 | -6.27 |
延庆 | 0.07 | 0.25 | -1.07 | -5.97 |
怀柔 | 0.07 | 0.29 | -0.22 | -6.15 |
密云 | 0.01 | 0.28 | 0.12 | -6.53 |
平谷 | 0.07 | 0.24 | 0.15 | -6.89 |
Table 3 The soil relative moisture at 8 o'clock and 20 o'clock during different time ranges表3 不同时间范围8∶00与20∶00的土壤相对湿度 |
时间范围 | 时刻 | 土壤相对湿度 |
---|---|---|
所有时长 | 整体 | 0.3906 |
8∶00 | 0.3901 | |
20∶00 | 0.3911 | |
分期前 | 整体 | 0.4101 |
8∶00 | 0.4096 | |
20∶00 | 0.4105 | |
分期后 | 整体 | 0.3617 |
8∶00 | 0.3608 | |
20∶00 | 0.3621 | |
10月 | 整体 | 0.4247 |
8∶00 | 0.4245 | |
20∶00 | 0.4250 | |
11月 | 整体 | 0.3889 |
8∶00 | 0.3885 | |
20∶00 | 0.3892 | |
12月 | 整体 | 0.3582 |
8∶00 | 0.3573 | |
20∶00 | 0.3590 |
Fig. 8 Spatial interpolation variation of soil relative moisture in Beijing city图8 北京市土壤相对湿度空间插值变化 |
[1] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[2] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[3] |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[4] |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[5] |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[6] |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[7] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[8] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[9] |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[10] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[11] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[12] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[13] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[14] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[15] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[16] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[17] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[18] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[19] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[20] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[21] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[22] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[23] |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
[24] |
[
{{custom_citation.content}}
{{custom_citation.annotation}}
|
{{custom_ref.label}} |
{{custom_citation.content}}
{{custom_citation.annotation}}
|
The authors have declared that no competing interests exist.
/
〈 |
|
〉 |