climate change indices

7/31/2019 Climate Change Indices

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Climate Change Indices

Climate Change and Water Resources CE74.9002

Water Engineering and Management (WEM)

School of Engineering and Technology (SET)

Asian institute of Technology (AIT)

By: I Putu Santikayasa


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Introduction

A main objective of constructing climate

extremes indices is to use for climate change

monitoring and detection studies

Change in the frequency or severity of

extreme climate events would have profound

impacts on nature and society

Very important to analyze extreme events

Need daily data very difficult task


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Introduction

Need to develop, calculate, and analysis a suite ofindices so that individuals, countries, and regionscan calculate the indices in exactly the same waysuch that their analyses will fit seamlessly into

the global picture Furthermore, need toolkits including software,

documentation, and other material to guide thecalculation and use of climate change detection

indices and climate data homogenization,improvement of global coverage and assessmentof indices.


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Climate Indices

Climate indices is used to monitor climate

change as and when is happens.

The indices based on daily temperature and

precipitation as data input

Some of them based on thresholds that are

relevant on particular application

40 indices was approved 27 indices

consider to be core indices


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Climate Indices

IDIndicator name

Definitions UNITS

FD0Frost days

Annual count when TN(daily minimum)25CDays

ID0Ice days

Annual count when TX(daily maximum)20C

Days


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Climate Indices

GSL

Growing seasonLength Annual (1st Jan to 31

st Dec in NH, 1st July to30th June in SH) count between first span ofat least 6 days with TG>5C and first spanafter July 1 (January 1 in SH) of 6 days withTG


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Climate Indices

TN10pCool nights

Percentage of days when TN90th percentile Days

WSDI

Warm spell

durationindicator

Annual count of days with at least 6consecutive days when TX>90th percentile

Days


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Climate Indices

CSDI

Cold spelldurationindicator

Annual count of days with at least 6consecutive days when TN=1.0mm) in the year

Mm/day


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Climate Indices

R10

Number of heavyprecipitation days Annual count of days when PRCP>=10mm Days

R20

Number of veryheavy

precipitation days

Annual count of days when PRCP>=20mm Days

Rnn

Number of daysabove nn mm Annual count of days when PRCP>=nn mm,

nn is user defined thresholdDays

CDD

Consecutive dry

daysMaximum number of consecutive days withRR=1mmDays


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Climate Indices

R95p

Very wet days

Annual total PRCP when RR>95th percentile Mm

R99p

Extremely wet days

Annual total PRCP when RR>99th percentile mm

PRCPTOT

Annual total wet-

day precipitation

Annual total PRCP in wet days (RR>=1mm) mm


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Climdex

Climdex : Microsoft Excel based program that

provides an easy-to-use software package for

the calculation of indices of climate extremes

for monitoring and detecting climate change

Developed by Byron Gleason at the National

Climate Data Centre (NCDC) of NOAA, and has

been used in CCl/CLIVAR workshops onclimate indices since 2001


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Climdex v.s RClimdex

Climdex

Ms. Excelplatform

Running underWindow

Difficult to fix thebug

RClimdex

R platform

Free Powerfull for

statisticalanalysis

Running under

window and unix Relatively easy to

fix the bug


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Rclimdex ver. 1.3

Used to calculate climate change indices

27 core indices recommended by the

CCl/CLIVAR Expert Team for Climate Change

Detection Monitoring and Indices (ETCCDMI)

Developed under R 1.84 or higher

Limitation:

Simple data quality control

Not include Data homogenization


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Please Remember!!:

1. Not all indices are calculated on a monthly basis.

2. Monthly indices are calculated if no more than 3 days are missingin a month, while annual values are calculated if no more than 15days are missing in a year.

3. No annual value will be calculated if any one months data are

missing.4. For threshold indices, a threshold is calculated if at least 70% of

data are present.

5. For spell duration indicators (marked with a *), a spell cancontinue into the next year and is counted against the year in

which the spell ends e.g. a cold spell (CSDI) in the NorthernHemisphere beginning on 31st December 2000 and ending on 6thJanuary 2001 is counted towards the total number of cold spells in2001


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Software and user manual :

http://cccma.seos.uvic.ca/ETCCDMI/software.shtml


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How to use RClimdex

R software is required to run Rclimdex

Connect to R Project website:http://www.r-project.org

Download * Install the program

*For window user : download window setup

For unix user: download proper precompiledbinaries (source code may need to bedownloaded and compiled)
http://www.r-project.org/http://www.r-project.org/http://www.r-project.org/http://www.r-project.org/http://www.r-project.org/


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How to use RClimdex

Data format:

1. ASCII text file

2. Columns as following sequences: Year, Month,

Day, PRCP, TMAX, TMIN. (NOTE: PRCP units =millimeters and Temperature units= degreesCelsius)

3. The format as described above must be spacedelimited

4. Missing data must be coded as -99.9; datarecords must be in calendar date order. Missingdates allowed.


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How to use RClimdex

Sample data:

Year

Month

Day

Precipitation(mm)

TMax

(oC)

TMin

(oC)


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How to use RClimdex

1. Load

RClimdex

2. Load

Data->Run

QC

3. IndicesCalculation


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1. R consol prompt >

Type: source (rclimdex path)

source("C:\\climateindices\\rclimdex.r")

source (http://cccma.seos.uvic.ca/ETCCDMI/RClimDex/rclimdex.r)

2. File > Source R code

Load RClimdexLoad Data->Run

QCIndices Calculation
http://cccma.seos.uvic.ca/ETCCDMI/RClimDex/rclimdex.rhttp://cccma.seos.uvic.ca/ETCCDMI/RClimDex/rclimdex.r


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Prerequisite for indices calculations

Replace all missing values (currently coded as -

99.9) into an internal format that R recognizes

Replace all unreasonable values into NA




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What will be checked?

Daily precipitation amounts less than zero

Daily maximum temperature less than dailyminimum temperature

QC also identifies outliers in daily maximum andminimum temperature

The outliers are daily values outside a regiondefined by the user

Unreasonable values are identified automaticallybut identification of outliers in temperature datarequires input from the user


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Data QC files

____tempQC.csv unreasonable

temperature

____prcpQC.csv unreasonable precipitation

____tepstdQC.csv all possible outliers in

daily temperature with the dates on which

those outliers occur

____indcal.csvQCd data and will be used

for the indices calculation


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RClimDex is capable of computing all 27 coreindices

Parameter input:

First and last year of base period for the thresholdcalculation

Station Latitude (SH negative)

daily precipitation threshold, P (in mm)

Upper and Limit of Day High

Upper and Limit of Day Low




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Selection of indices

Result will be stored as excel file and jpeg

format

Jpeg format: trends computed by linear least

square (solid line) and locally weighted linear

regression (dashed line)




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Class exercise


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Case study:

Analyze climate change indices by using data

from your country

Due date: 29th

March 2012Submitted to Dr. Sangam


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Thank you

Have a nice day

climate change indices

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