摘要

土壤濕度在垂向空間和時間上具有很高的變異性，而土壤濕度的變化會使得地表蒸發(fā)量、地表反射率、土壤熱容量等發(fā)生改變，進而改變地表對大氣的能量輸送，最終影響氣候。深入分析土壤濕度的變化，對于研究某地區(qū)的土壤性質(zhì)和短期的氣候情況都具有極大的作用。本論文利用xx水文實驗站1997～2005年的逐日平均氣溫、降水、蒸發(fā)和水位資料以及同時段的逐旬平均土壤濕度資料，分析氣象要素的變化特征和土壤濕度的時空變化特征、自相關(guān)性，進而研究土壤濕度的記憶能力，探討土壤濕度與前后期降水和氣溫的動態(tài)關(guān)系。主要結(jié)論如下：

(1)研究區(qū)由于不同年份氣候、環(huán)境的差異，土壤濕度存在年際間差異，土壤濕度變化受到上下邊界影響明顯，即降水、氣溫和地下水位等。土壤濕度在年內(nèi)有明顯的兩干兩濕期。從表層到深層，土壤濕度呈現(xiàn)增大的趨勢。

(2)研究區(qū)土壤濕度的自相關(guān)性較好，隨著土層的加深相關(guān)系數(shù)變大。土壤的記憶能力隨季節(jié)和土壤深度而變化。秋季的記憶能力最好，約2～3個月。表層的土壤記憶能力小于深層。

(3)研究區(qū)土壤濕度受氣溫和降水影響顯著。土壤濕度與前期和同期的氣溫呈負相關(guān)，與半年后的氣溫呈正相關(guān)。土壤濕度與前期降水呈正相關(guān)，與1～2月后的降水呈負相關(guān)。土壤濕度在春秋季節(jié)與同期的降水和氣溫相關(guān)性顯著。垂向上變化較復雜。

(4)利用水文模型系統(tǒng)（HMS）模擬出1997～2005年0.05、0.15、0.35m層的土壤濕度，與觀測序列進行對比，發(fā)現(xiàn)在土壤處于穩(wěn)定濕潤時期時，模擬的效果最好。

關(guān)鍵詞：土壤濕度；記憶能力；降水；溫度；相關(guān)系數(shù)

 

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 錄

摘要 I

Abstract II

目 錄 IV

第一章  緒論 1

1.1引言 1

1.2國內(nèi)外研究進展 2

1.2.1土壤濕度的時序特征 2

1.2.2土壤濕度的垂向空間上差異 2

1.2.4土壤濕度的記憶能力 3

1.2.5土壤濕度與氣候關(guān)系 3

第二章 xx實驗站概況及基本要素分析 5

2.1xx水文水資源實驗站概況 5

2.2氣象要素分析 7

2.2.1氣溫 7

2.2.2降水 8

2.2.3蒸發(fā) 10

2.2.4地下水位 10

2.3 本章小結(jié) 11

第三章 土壤濕度的時間分布特征 12

3.1 季節(jié)變化 12

3.2年際變化 16

3.3垂向分布 18

3.4本章小結(jié) 20

第四章 土壤濕度的記憶能力 21

4.1計算方法 21

4.2自相關(guān)分析 21

4.3記憶能力 25

4.4本章小結(jié) 27

第五章 土壤濕度與氣溫和降水的關(guān)系 28

5.1與溫度關(guān)系 28

5.1.1旬尺度上的相關(guān)關(guān)系 28

5.1.2季節(jié)尺度上的相關(guān)關(guān)系 29

5.2土壤濕度與降水關(guān)系 32

5.2.1旬尺度上的相關(guān)關(guān)系 32

5.2.2季節(jié)尺度上的相關(guān)關(guān)系 33

5.3本章小結(jié) 35

第六章 土壤濕度模擬分析 36

6.1模型原理及操作 36

6.2模擬分析 38

6.3原因分析及建議 47

6.4本章小結(jié) 48

第七章 總結(jié)與展望 49

7.1總結(jié) 49

7.2展望 50

參考文獻 51

致謝 52