Applications of ClimatologyApplications of Climatology

Syed Taha AhmedSyed Taha Ahmed

AR - 016AR - 016

Climate is Climate is commonly defined as the commonly defined as the weather averaged over a weather averaged over a long period of time. In long period of time. In other other words, climate is the words, climate is the average weather average weather conditions experienced in conditions experienced in a particular place a particular place over a long period.over a long period.

Climate is defined as the collective state of the

atmosphere for a given place over a specified interval of

time.

Aim’s of climatology, is the object to climatology to make

us familiar with the average condition of the

atmosphere in different part of the earth’s surface, as well as to inform us concerning any departures from these

conditions which may occur at the same place during long

intervals of time.

There are three principal approaches to the study of There are three principal approaches to the study of climatologyclimatology::

The physical climatology approach seeks to explain the differences in climate

in light of the physical processes influencing climate and the processes producing

the various kinds of physical climates

Descriptive climatology typically orients itself in terms of geographic

regions ;it is often referred to as regional climatology. A description of the various types of

climates is made on the basis of analyzed statistics from a particular area.

Dynamic climatology attempts to relate

characteristics of the general

circulation of the entire atmosphere to the climate. Dynamic

climatology is used by the theoretical

meteorologist and addresses dynamic and thermodynamic effects.

Compute decadal means and standard Compute decadal means and standard deviation for SLP for two different deviation for SLP for two different

decades, compute the decades, compute the

t-statistic, and plot the 5% level as t-statistic, and plot the 5% level as stipplingstippling. .

Calculates monthly Calculates monthly climatologies and then climatologies and then

conducts an eof conducts an eof analysis. analysis.

Demonstrates the use of Demonstrates the use of clmMonLLT and  and stdMonTLLto derive climatology to derive climatology and the interannual variability. Though this example derives the and the interannual variability. Though this example derives the

climatology based on the entire time period, a subset may be used by climatology based on the entire time period, a subset may be used by

using either conventional subscripting or coordinate dimensions.using either conventional subscripting or coordinate dimensions.

Demonstrates the use Demonstrates the use of of clmMonLLT to  to derive a zonally derive a zonally

averaged annual averaged annual cycle. cycle.

Calculate the daily mean Calculate the daily mean annual cycle and daily annual cycle and daily

anomalies from the anomalies from the mean annual cycle. For mean annual cycle. For illustration: illustration: (a)(a) compute  compute

raw and smoothed raw and smoothed annual annual

cycles; cycles; (b)(b) create a  create a netCDF file of the daily netCDF file of the daily

anomalies;anomalies;(c)(c) plot  plot results. results.

This example only uses 5-This example only uses 5-years of data. Hence, there years of data. Hence, there is considerable day-to-day is considerable day-to-day variability in this examplevariability in this example. .

The smoothed The smoothed annual cycle can be annual cycle can be thought of as the thought of as the values that would be values that would be obtained if there obtained if there was an infinite was an infinite ensemble of data ensemble of data under the same under the same

forcing conditions.forcing conditions.

  (a)(a) Read files containing year-month data,  Read files containing year-month data, (b)(b) create climatologies spanning user  create climatologies spanning user specified years specified years (c)(c) plot November-April and May-October climatologies over a  plot November-April and May-October climatologies over a

user specified regionuser specified region