About: This post is actually a summary of a research project I took under INSPIRE-SHE Scholarship Program by Dept. of Science and Technology, Govt. of India. My plan was to make the content open-source on the web that faults could be corrected by time. The language is simple and very easy to understand and the ease of understanding is focused to A-level (10+2) students and beyond.

#### Abstract

The present project is based on 20 years of meteorological data provided by IMD approved weather station at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar. The observations are taken twice a day and therefore fourteen times a week. My analysis is based on the weekly reports provided by the agro-meteorological department. The main aim of this project is to develop my analytic skills in meteorology and to provide some better ideas on the meteorological studies. The meteorological observatory at Pantnagar is located at 290 N latitude, 79.30 E longitude and 243.84 m altitude under N. E. B. Crop Research Center. Pantnagar region lies in the Tarai belt of Uttarakhand state of India. It is comparatively hot and wet place to nearby places like famous hill station Nainital. The annual rainfall is about 145 cm, which has a lot of variations throughout the year. The rainy season starts at the end of June and end in September. Maximum rain is received from south-west monsoon during four months rainy season from June to September. The soil of this region is good for agriculture and holds enough moisture to produce good crops. The average pH value of the soil is 7.2 – 7.4. The temperature variation is very large, as summer holding temperature maxima of around 42-45 degree Celsius while in winter it falls heavily to 2-4 degree Celsius.

This report was aimed to study and analyze the collected weekly data within the limited time period of two months, as proposed by DST, Govt. Of India under INSPIRE-SHE summer project.

### Introduction

Meteorology is a word made by a combination of two Greek words ‘Meteors‘ which means ‘atmospheric‘ or ‘lofty‘ and ‘logos‘ which means discourse or science. Therefore we can define Meteorology as the Science of Atmosphere. Meteorology is actually the study of atmospheric processes using extensive use of applied physics. The science of atmosphere involves the static and dynamic components of atmosphere, so they when combined called weather.

#### Constitution of Atmosphere

The atmosphere of earth is a relatively thin sheet of gas firmly attracted to the surface by gravitational force of earth. The atmosphere is mainly treated to be made of something special that is invisible and odorless substance called Air. Air is the most important component of earth atmosphere. When we say ‘Atmosphere’, in behavior we mean ‘Air’. Air itself has two constituents: Distinct and Variable!

Distinct gaseous constituents are major and cover almost 100% of atmosphere. Main gases present in atmosphere are Nitrogen (78%) and Oxygen (21%) and minor constituents (~1%) are Argon types of  inactive gases. Main Variable constituents are water-vapor, ozone, carbon dioxide and dust. The availability of these constituents depend upon the location at the earth.

The standard state of atmosphere has been well explored with the help of meteorological and satellite observations. The paragraph below will feature the layers of atmosphere. The temperature and physical standards of every atmospheric layer has different values. Hence , it is highly recommended to study about them before we go ahead. The lowest layer contains about three fourth of the mass and almost all the moisture and dust of the atmosphere. It is called the troposphere. All the meteorological phenomena which are called Weather and thus highly related to this project are confined to the troposphere. The top of troposphere is called tropopause. The height of tropopause varies from 8km (at the poles) to 16km (at equator).

In troposphere the temperature decreases with the elevation at an average rate of 6.5 degree Celsius per km. This is known as the lapse rate. Above the tropopause is the stratosphere which is free of daily and annual heating of earth’s surface and contains very little dust and moisture. Stratosphere contains a major portion of lifesaving Ozone. Stratopause is located at 30 to 50km above the earth surface as the upper limit of stratosphere. Above stratosphere, there are the mesosphere and mesopause, a warm layer at 80km above the earth surface. The fourth major layer above the mesopause is ionosphere which contains a very little pressure of about 0.01milibars at 90 km. This layer contains ultraviolet radiation, satellites etc. Ionosphere merges gradually into the outermost  shell called the exosphere. In exosphere the mean free path is very large and the atmosphere has lost the property of continuum.

As already mentioned troposphere is the domain of study of  meteorology with an extension to stratosphere involving ozone.

#### Meteorological observations

Using applied physics, engineers do periodical measurements on meteorological parameters to understand long term or short term atmospheric phenomena. The meteorological parameters are like coordinates to explain atmospheric observations and these are dependent of conditions (time and location). There are a number of parameters depending on the meteorological observations one uses, out of which some parameters are most important and shall be used in this project are:

1. Atmospheric pressure
2. Wind Velocity

3. Wind direction

4. Temperature

5. Humidity

7. Sunshine

8. Precipitation (rain, snowfall, hail)

9. Evaporation

Meteorological instruments are used to collect the data of these parameters at meteorological observatory or the weather station. In India there are a number of weather stations which are regulated by Indian Meteorological Department (IMD). All weather stations work on specific standards formulated by IMD for the location. The meteorological data can be obtained from the weather stations. I have collected the data from weather station Pantnagar, Uttarakhand. Generally the observations are taken twice a day, i.e., at 07:12 & at 14:12 hours.

The minimal understanding of physics of meteorological parameters is required before we can do statistical observations.

##### Atmospheric Pressure

All in One Equipments

This is the force exerted per unit surface area of earth at a location. Atmospheric pressure is usually measured by Fortins barometer consisting of an inverted U-tube filled with mercury kept in a cistern, or an aneroid barometer. The instrument which records the variation of the atmospheric pressure with respect to time is called a barograph.

The standard atmospheric pressure is $1.02 \times 10^5 N/m^2$ .

##### Wind Direction and Wind Velocity

Wind Gauge

Air in the motion is called the wind. The horizontal component of the air in movement parallel to the earth’s surface is generally referred to as wind while the vertical components are referred to as the air currents. Measurement of wind direction is extremely easy and is measured by wind vane, while measurement of wind velocity is a little tricky and is measured using the cup anemometer.

##### Temperature

Thermometers

The most studied parameter of meteorology is temperature and it can be measured simply using mercury thermometer in degree Celsius. A continuous record of temperature with time can be obtained by an automatic recording instrument called the thermograph. The thermograph measures the temperature using the principle that a bimetallic strip changes its shape under the influence of the change in temperature. The maximum and minimum temperatures at a station are measured by maximum thermometer and minimum thermometer respectively. The mean daily temperature is computed as the arithmetic average of the maximum and minimum temperatures recorded on  that day. The daily range is the temperature difference between maximum and minimum temperatures for the particular day. The mean monthly temperature is computed as the arithmetic average of the mean daily temperatures of all days in a month. The mean annual temperature is the arithmetic average of the mean temperatures of all days in an year. The normal daily temperature is the average of the daily mean temperatures for a period of 30 years. Similarly, the normal monthly temperature is the average of the mean monthly temperatures for a 30 years. The normal annual temperature is the average of the mean annual temperatures for a 30 years.

##### Humidity

Also known as relative humidity, humidity is measured by the psychrometer. The continuous recording of humidity with time is done by automatic recording instrument called hydrographer. Humidity is relative quantity and is measured in unit per cent and is defined by the percentage measured by the ratio of actual and saturation vapor pressures at a given temperature.