Investigating the trend of temperature and precipitation changes in the last half century (1962-2011) at the Bandar Anzali observation station.

Academic thesis for obtaining a master's degree

Field: Geography Orientation: Climatology in environmental planning

Abstract

Different climatic parameters such as temperature, humidity and rainfall in a place are among the factors that influence the climate of that region and their knowledge determines the climate of that region. Climate change is one of the most important climate issues that have attracted the attention of researchers and even heads of governments and organizations in recent years due to its effects on political, social, and economic activities. . . It has, has been busy with itself. The area studied in this research is Bandar Anzali observation station, in the north of the country. The parameters used in this research are rainfall and annual temperature for fifty years (1962-2011) which were received from the General Meteorology Department of Gilan Province. The statistical deficiencies of some series were solved using the method of differences and ratios. In order to investigate and recognize changes in time series, Kendall's t-test and Man-Kendall's graphic-statistical method were used, and the type and time of data changes were determined. The results of the research show that the monthly changes in precipitation and temperature in the studied area indicate changes in these elements. These changes include both increasing and decreasing types, so this assumption is proven and considering that the two graphs for both precipitation and temperature variables have only one meeting point, so there is a significant trend. Also, during the studies, it is clear that we have witnessed an increase in temperature in this city in recent years.

Key words: Climate change, Man Kendal, temperature and precipitation, Bandar Anzali

Introduction

One of the most important topics in the scientific circles of the world is the climate and its change as an irreversible situation, which has been the focus of attention of most researchers in scientific fields for the last few decades. A slight perturbation of the world's climate balance has caused the average global temperature to show a tendency to increase (IPCC 2001a), so that the Intergovernmental Panel on Climate Change reported in 2001 that the climate is changing and global warming is occurring (Drakop and Vikena, 2005). This phenomenon is due to the increase in the concentration of greenhouse gases in the atmosphere (Dettinger et al., 2004). Many natural disasters can be directly and indirectly attributed to climate change. So, based on the results of climate change studies in the Mediterranean basin, the existence of a relationship between the decrease in temperature and precipitation and the lack of water and the increase in the risk of forest fires in the region has been proven (Painel et al., 1998). In general, two statistical methods, parametric and non-parametric, are presented in order to check the presence or absence of trends and analysis of time series and climate change, and non-parametric methods have a relatively wider and more impressive application (Takiuchi and Ishidari, 2003). Parametric methods are mainly based on a regression relationship between data series with Student's time, among the most common non-parametric methods. But for series where t is constant. A special statistical distribution test cannot be applied to them and they have a lot of skewness or elongation, the use of non-parametric methods is more appropriate (Behirat and Mehmtik, 2003). Climate change does not necessarily mean changes in precipitation and temperature (Clark, 2003). On the other hand, the proof of the existence of a significant trend in a time series of rainfall alone cannot be a conclusive proof of the occurrence of climate change in a region, but it strengthens the assumption of its occurrence (Cyrano et al., 1999). Weather and climatic conditions have undergone changes over the years, that is, every few million years, the earth is cold and warms up again. Several elements such as temperature, humidity and pressure are effective in shaping weather. Changes in temperature, precipitation and other climatic elements may be seasonal or may be long-term and occur over years.. In this research, an attempt has been made to compare the seasons of different years, for example, to compare the amount of precipitation in different summers and to determine the differences and reasons for these differences.

1. Showing the years with the most increase in temperature and decrease in precipitation and its possible reasons

2. Examining the process of changes and how the climate of the city will be in the next few years

1-2. Research Hypotheses

According to the role and importance of hypotheses in scientific research, at this stage, the hypothetical and proposed theorems were compiled and explained within the framework of the research problem, and the following hypotheses are proposed:

1- It seems that the temperature of Bandar Anzali city has been increasing during the last half century and the climate of this city is changing to a warm climate.

2 - Rainfall in Bandar Anzali during the last 50 years is increasing.

3-Rainfall has changed significantly in the study area during the statistical period.

1-3. The objectives of the research

     Climate change is important from all aspects and in many sciences of the world. In this research, in line with these issues, the following goals are important from both a scientific and practical point of view, and perhaps these goals are just a part of the goals of scientific changes.

- Providing a suitable method for other researchers to study in this field.

- Using the research results for the officials to use in various matters.

- Planning the officials for the future.

1-4. Research question

According to the objectives of the research and the hypotheses raised, the most important questions that are raised in this research are as follows:

1- Is the temperature of Bandar Anzali city increasing during the last half century and is the climate of this city changing to a warm climate? 

3- Is there a significant temporal and spatial change in rainfall during the statistical period in the study area?

1-5. Research method According to the recommendations of the World Meteorological Organization, the review of long-term climate statistics can show its changes and characteristics to a large extent. Therefore, the long-term data of the annual temperature and total seasonal precipitation, the annual meteorological station from 1961 to 2011, part of these statistics were obtained from the website of the National Meteorological Organization, and the other part, which is related to recent years, was prepared by referring to the General Directorate of Meteorology of Gilan Province. Using the double mass method, some of the statistical deficiencies of the series were reconstructed. In line with the intended goals, the research is descriptive.

1-5-1. The method of information gathering. In the stage of information gathering, it was done based on the library method. Through the study and use of relevant books and publications, as well as various articles, an attempt was made to become more familiar with the research conducted in this field. Using the available statistical information from the Meteorological Organization of the country and also the General Directorate of Meteorology of Gilan Province. 1-5-2. Information gathering tools include: tests, tables, books, articles, databases and computer networks, maps, statistics, charts, etc. . used.

1-6. Information analysis method

After collecting data and resources and classifying and organizing them using statistical methods and tests. . . related to the topic used for analysis.

1-7. Obstacles and limitations of research

Considering that every researcher faces problems and limitations in the stages of his work. Among the most important of these problems, the following can be mentioned:

Lack of basic and accurate information in recent years, especially in the field of statistics and weather stations

Lack of sufficient and necessary statistics and information

Difficult access to new statistics

Conversion of solar months to Gregorian and vice versa in order to unify all statistics

Research background

   in climate literature Cosmology, many studies have been done on contemporary climate changes.