Analyzing and IdentifyingRegional Changes of Hot and Cold Zonesin Iran indifferent Periods

IntroductionTemperature can be considered as one of the most important elements of the climate system to changes that can transform any local weather conditions. These changes can occur in many ways due to the heterogeneous distribution of solar energy inthe Earth's surface (Nazemosadat,2009). Several factors can affect the temperature of azone. Thus, thisstudy can reflect those factors. Location factors such as topography and latitude location as well as theinfluence of neighbors, atmospheric circulation systems, and many other factors have an undeniable role in the development of the temperature. It should be notedthat temperature or any other climatic element in each location will be similar to adjacent areas. In this case, it is obvious that the degree of similarity between samples ismore likely to be closer. Because, if there is a spatial structure, changes in the same area have a greater chance of influencing your space near to the outer space of their own (Hassanipak, 2009). The neighboring area knows that the formation of a climate temperature is of utmost importance.Therefore, it is important to know the neighborhoods that cause the formation of a climate of temperature. Generally, the main cause of temperature differences in different parts of the planet is the difference in angles of sunlight in different geographic latitudes, but if this factor is accepted as the only factor affecting temperature variations, temperature changes over the course of one year and in different years of regular course If it is not so in nature, and factors such as the topography of the area, the direction of the slopes, the soil cover, the distances or proximity to the water zones, and the regional and planetary atmospheric systems of this order will overcome. The climate and temperature hotbeds were less studied by climatologists, but these zones were considered by climate experts under other titles such as the identification of thermal waves (hot temperature zones) and cold waves (cold temperatures).
Material and MethodsIn this study, to identify zones of warm and cold temperatures, daily temperature of283 daily synoptic stations of Iran’s Meteorological Organization has been extracted. This group of data interpolation values and the daily temperatures across the country between1961and2010(18183 days) was obtained and used as the main database. 15 × 15 km spatial resolution of the data is written in the image of Lambert conical shape. The cell density of 7101 cells is around. Finally, the matrix is composed of 7101 × 18183 was used as the main database. In order to investigate changes in zones where hot and cold temperatures, the statistical period equal to five times and divided into temperature zones in each period hot and cold identifying been examined and changes in the next period. It should be noted that in this study for the calculation of MATLAB and the Mapping software is used SURFER. First, to identify zones of hot and cold temperatures have used cluster analysis.
In order to validate the hot and cold zones such as temperature indicators Davies-Bouldin index validation, Silhouette index and discriminant analysis were used.
Results and DiscussionThe results of this study showed that:- Zones of cold temperatures on average 12.3 percent of the country's area, which is further along the Zagros Mountains, North West and small parts of the North East in the covers.
- The extent of an area of cold temperature to the recent period, in addition to the reduction has been cold-zone average temperature has increased significantly. For example, an area of cold temperature in the decade 1341 to 1350 with an average temperature of 7/12 nearly 63/26 percent of the country is covered while the fifth period (1381 to 1390) is about the average temperature 7/13 ° C with an area of 13.6 percent.
In addition to this it can be deduced that the role of greenhouse Persian Gulf zone heat in this region of the country has a great impact.
- Warm temperature zone countries, following the recent period of global warming has increased.1 ° C increase.
- Spatial distribution of hot and cold temperatures across the country most affected by local factors such as altitude and latitude. Meanwhile, more obvious is the height of the cold temperature zone so that cold zones of temperature and altitude has been more uneven matches.
ConclusionThe aim of this study is to identify zones of warm and cold temperatures and changes during the period are different. For this purpose, the daily temperature data for 238 synoptic stations during the period 1341 to 1390 the country extracted Meteorological Organization. To identify changes in hot and cold temperatures zone period equal to five times (1350-1341, 1360-1351, 1370-1361, 1380-1371 and 1390-1381) and split hot and cold temperature zones in each period have been detected and changes in the next period examined. To identify the zone cluster analysis and multivariate statistical methods to validate the temperature of indicators such as hot and cold zones, Davies-Bouldin index validation (DBI), Silhouette index (SI) and discriminant analysis is used. The results of this study indicate that the temperature of the heat zones In the recent period, in addition to the spatial range to higher latitudes (towards the northern latitudes and almost 2.3 per cent) is drawn over the recent period has increased 3.1 degrees Celsius. This is while Iran to the cold temperature zones recent period In addition to the spaciousness of reducing the amount of temperature increase is tangible So that the average temperature of the cold zone in the first period (1341-1350) with a temperature 7/12 ° C range, which is 4/26 of the fifth period (1390-1381) the extent to 8/25 at 4 / 13 degrees Celsius, which represents an increase in temperature of 7.0 ° C cold zone. The results of the validation Davis-Bouldin index, Silhouette index and discriminant analysis showed that generally cold and heat zones of the top 98% in their respective groups, respectively.