xx水文实验站土壤湿的时间尺分析与模拟.docx

 

摘要

土壤湿度在垂向空间和时间上具有很高的变异性，而土壤湿度的变化会使得地表蒸发量、地表反射率、土壤热容量等发生改变，进而改变地表对大气的能量输送，最终影响气候。深入分析土壤湿度的变化，对于研究某地区的土壤性质和短期的气候情况都具有极大的作用。本论文利用xx水文实验站1997～2005年的逐日平均气温、降水、蒸发和水位资料以及同时段的逐旬平均土壤湿度资料，分析气象要素的变化特征和土壤湿度的时空变化特征、自相关性，进而研究土壤湿度的记忆能力，探讨土壤湿度与前后期降水和气温的动态关系。主要结论如下：

(1)研究区由于不同年份气候、环境的差异，土壤湿度存在年际间差异，土壤湿度变化受到上下边界影响明显，即降水、气温和地下水位等。土壤湿度在年内有明显的两干两湿期。从表层到深层，土壤湿度呈现增大的趋势。

(2)研究区土壤湿度的自相关性较好，随着土层的加深相关系数变大。土壤的记忆能力随季节和土壤深度而变化。秋季的记忆能力最好，约2～3个月。表层的土壤记忆能力小于深层。

(3)研究区土壤湿度受气温和降水影响显著。土壤湿度与前期和同期的气温呈负相关，与半年后的气温呈正相关。土壤湿度与前期降水呈正相关，与1～2月后的降水呈负相关。土壤湿度在春秋季节与同期的降水和气温相关性显著。垂向上变化较复杂。

(4)利用水文模型系统（HMS）模拟出1997～2005年0.05、0.15、0.35m层的土壤湿度，与观测序列进行对比，发现在土壤处于稳定湿润时期时，模拟的效果最好。

关键词：土壤湿度；记忆能力；降水；温度；相关系数

 

Abstract

The highly vertical spatial and temporal variability of soil moisture leads to the further study of soil moisture. The variable feature of soil moisture can affect the surface evaporation, surface reflectance, soil heat capacity etc. and then the energy delivery of surface to the atmosphere and finally the climate. Deep and systematic analysis on changes of the soil moisture is helpful for the study of soil properties and the short-term climate situation. Firstly, using the observed soil moisture, daily average temperature, precipitation, evaporation, groundwater depth data of Wudaogou experiment station from 1997 to 2005.Based on these studies, we then analysis the temporal and spatial variation and the correlation of soil moisture and the relationship with meteorological elements. Finally, we study the timescale to find the relationship between precipitation and temperature and soil moisture. Main results are as follows:

(1)Due to the differences between the annual year’s climate, the environment, the soil moisture of the study area varies with year and depth. Soil moisture change is mostly affected by the upper and lower boundaries, such as temperature, precipitation and groundwater depth. Soil moisture has two significant dry period and wet period in a year. From the surface to the deep, the soil moisture shows an increasing tendency.

(2)The soil moisture of this area has great autocorrelation, with an increasing tendency from the surface to the deep. The timescale of soil moisture varied with season and soil depth. The autumn soil moisture timescale is larger than the other three seasons, about 2～3 months. The timescale of 0～10cm is larger than that in the deep. 

(3) There is a significant relationship between the soil moisture, precipitation and temperature. There is significant negative correlation coefficient between the soil moisture and the prior and the simultaneously temperature, and positive correlation between the soil moisture and the temperature of half a year later. There is significant positive correlation coefficient between the soil moisture and the subsequent precipitation, and the negative correlation with the precipitation of 1～2 months later. There is also significant relationship between the soil moisture in autumn and the simultaneously precipitation and temperature. Vertically change is more complex.

（4）Use the Hydrological Model System(HMS) to simulate the soil moisture from 1997 to 2005 of 0.05, 0.15, 0.35m layer and compare the data with the observed soil moisture. The results show that in the stable moist period, the simulation results are most consistent with the observed soil moisture.

Key words: soil moisture, memory timescale, precipitation, temperature, correlation coefficient

 

目 录

摘要 I

Abstract II

目 录 IV

第一章  绪论 1

1.1引言 1

1.2国内外研究进展 2

1.2.1土壤湿度的时序特征 2

1.2.2土壤湿度的垂向空间上差异 2

1.2.4土壤湿度的记忆能力 3

1.2.5土壤湿度与气候关系 3

第二章 xx实验站概况及基本要素分析 5

2.1xx水文水资源实验站概况 5

2.2气象要素分析 7

2.2.1气温 7

2.2.2降水 8

2.2.3蒸发 10

2.2.4地下水位 10

2.3 本章小结 11

第三章 土壤湿度的时间分布特征 12

3.1 季节变化 12

3.2年际变化 16

3.3垂向分布 18

3.4本章小结 20

第四章 土壤湿度的记忆能力 21

4.1计算方法 21

4.2自相关分析 21

4.3记忆能力 25

4.4本章小结 27

第五章 土壤湿度与气温和降水的关系 28

5.1与温度关系 28

5.1.1旬尺度上的相关关系 28

5.1.2季节尺度上的相关关系 29

5.2土壤湿度与降水关系 32

5.2.1旬尺度上的相关关系 32

5.2.2季节尺度上的相关关系 33

5.3本章小结 35

第六章 土壤湿度模拟分析 36

6.1模型原理及操作 36

6.2模拟分析 38

6.3原因分析及建议 47

6.4本章小结 48

第七章 总结与展望 49

7.1总结 49

7.2展望 50

参考文献 51

致谢 52