# Calculating the Total Annual Precipitation

Initial Publication Date: September 8, 2015

#### Introduction

The objective of this step is to calculate the total annual depth of precipitation from a given precipitation time series . We have used the 15 minutes interval historical precipitation data, recorded at the weather station - COOP:122309 during the period 01/01/2000 - 12/31/2000, for this exercise.

## Conceptual Outcomes

Students demonstrate their understanding of precipitation time series records and the total annual precipitation in a region.

## Practical Outcomes

- Students learn to identify the units of the downloaded precipitation data.

- Students learn to calculate the total annual precipitation for a region from the precipitation time series using MS Excel.

30 minutes

## Computing/Data Inputs

• Numerical Data: Precipitation time series derived from 15-minutes interval historic precipitation data at NCDC station COOP-122309 : Precipitation time series (Excel 2007 (.xlsx) 26kB Sep7 15)

## Computing/Data Outputs

• Numerical Value: Total annual precipitation in the watershed

MS Excel

## Instructions

Precipitation data recorded in the NCDC dataset typically has the units: one-hundredth of an inch. Lets divide these values by 100 to get the precipitation time series in inches. Now, the total annual precipitation in your watershed is simply the sum of these precipitation values recorded in the year 2000. Very straightforward, isn't it ?