Abstract:
Physical characteristics of different features in desert is a reflection of severe thermal and climatic conditions. Inthis paper, diurnal surface temperature patterns of important surface features in Lut Desert were studied and therelationship among different surfaces analyzed. Diurnal trend in surface temperature of surface types, marl, dark sand, light sand, salt-affected soil, soul at 10 cm depth, as well as dry and wet air temperature within 15 days wererecorded in 2 hour intervals in the margin of Lut yardangs while correlations among these surface features and its
significance level were investigated. The knowledge of diurnal temperature pattern and calculation of correlationamong features can lead us to the understanding of the behavioral pattern and the trend of surfaces. The knowledge ofbehavioral pattern of correlation coefficients during different hours of the day provides the researchers the ability toproduce optimal models of thermal characteristics and to predict them. Additionally, thermal data of different sensor
systems along with their capability in the study of surface features in Lut Desert was evaluated. The results of thermaland inter-feature correlation analysis reveal a similar trend (at 8 AM and 4 PM) among various feature types. Thecorrelation coefficient of different surfaces shows the highest value at 6 AM and the lowest at 8 PM. The correlationcoefficient between sand and marl with grey sand and soil shows a non-linear trend at pre-noon hours while a linearand similar trend in the afternoon. Generally speaking, the correlation coefficient between surfaces at pre-noon hoursas compared to afternoon hours is completely non-linear and does not reveal any specific pattern. It seems that TIRdata acquired at 10 AM is the best choice in the study of Lut Desert and hence ETM+ and TM data can be used.
Machine summary:
"Diurnal trend in surface temperature of surface types, marl, dark sand, light sand, salt-affected soil, soul at 10 cm depth, as well as dry and wet air temperature within 15 days were recorded in 2 hour intervals in the margin of Lut yardangs while correlations among these surface features and its significance level were investigated.
Soil of desert regions due to a lack of moisture and accumulation of heat in a near surface crust, has a high day-time and low night-time temperature (Kaviani, 2001), so that as the severity of dryness increases in a region, the role of physical and thermal charactreristics of forming materials in the control of temperature pattern becomes prominent.
In this study surface temperature of such features as marl, gray sand, bright sand, saline soil, 10 cm depth of soil (referred to as subsurface, hereafter) along with wet and dry temperatures in Lut Desert form September 4, 2001 to September 18, 2001 for a period 15 days and in 2 hour intervals (form 6 AM to 8 PM) were recorded in a controlled manner.
High correspondence of correlation coefficient trend of surface temperature (saline and subsurface soil) during different hours of the day with other surface types shows their similar thermal characteristics.
The results summarized in table 4 indicate that TIR data acquired in morning hours and the midday images are the best options for separation of different feature and types of soil, based on thermal differences."