FD

Number of frost days

Annual count of days when daily minimum temperature < 0^oC.

SU

Number of summer days

Annual count of days when TX (daily maximum temperature) > 25^oC.

ID

Number of icing days

Annual count of days when TX (daily maximum temperature) < 0^oC.

TR

Number of tropical nights

Annual count of days when TN (daily minimum temperature) > 20^oC.

GSL

Growing season length

Annual (1^st Jan to 31^st Dec in Northern Hemisphere (NH), 1^st July to 30^th June in Southern Hemisphere (SH)) count between first span of at least 6 days with daily mean temperature TG>5^oC and first span after July 1^st (Jan 1^st in SH) of 6 days with TG<5^oC.

TX_x

Monthly maximum value of daily maximum temperature

Let TX_x be the daily maximum temperatures in month k, period j. The maximum daily maximum temperature each month is then:

TX_xkj=max(TX_xkj)

TN_x

Monthly maximum value of daily minimum temperature

Let TN_x be the daily minimum temperatures in month k, period j. The maximum daily minimum temperature each month is then:

TN_xkj=max(TN_xkj)

TX_n

Monthly minimum value of daily maximum temperature

Let TX_n be the daily maximum temperatures in month k, period j. The minimum daily maximum temperature each month is then:

TX_nkj=min(TX_nkj)

TN_n

Monthly minimum value of daily minimum temperature

Let TN_n be the daily minimum temperatures in month k, period j. The minimum daily minimum temperature each month is then:

TN_nkj=min(TN_nkj)

TN10p

Percentage of days when TN < 10^th percentile

Let TN_ij be the daily minimum temperature on day i in period j and let TN_in10 be the calendar day 10^th percentile centred on a 5-day window for the base period 1961-1990. The percentage of time for the base period is determined where: TN_ij < TN_in10

TX10p

Percentage of days when TX < 10^th percentile

Let TX_ij be the daily maximum temperature on day i in period j and let TX_in10 be the calendar day 10^th percentile centred on a 5-day window for the base period 1961-1990. The percentage of time for the base period is determined where: TX_ij < TX_in10

TN90p

Percentage of days when TN > 90^th percentile

Let TN_ij be the daily minimum temperature on day i in period j and let TN_in90 be the calendar day 90^th percentile centred on a 5-day window for the base period 1961-1990. The percentage of time for the base period is determined where: TN_ij > TN_in90

TX90p

Percentage of days when TX > 90^th percentile

Let TX_ij be the daily maximum temperature on day i in period j and let TX_in90 be the calendar day 90^th percentile centred on a 5-day window for the base period 1961-1990. The percentage of time for the base period is determined where: TX_ij > TX_in90

WSDI

Warm spell duration index

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

CSDI

Cold spell duration index

Annual count of days with at least 6 consecutive days when TN < 10^th percentile

DTR

Daily temperature range

Monthly mean difference between TX and TN

Rx1day

Monthly maximum 1-day precipitation

Let RR_ij be the daily precipitation amount on day i in period j. The maximum 1-day value for period j are: Rx1day_j = max (RR_ij)

Rx5day

Monthly maximum consecutive 5-day precipitation

Let RR_kj be the precipitation amount for the 5-day interval ending _k, period j. Then maximum 5-day values for period j are: Rx5day_j = max (RR_kj)

SDII

Simple precipitation intensity index

Let RR_wj be the daily precipitation amount on wet days, w (RR ≥ 1mm) in period j. If W represents number of wet days in j, then:

$$SDII_{j}={∑↙{w=1}↖W RR_{wj}}/W$$

R10mm

Annual count of days when PRCP≥ 10mm

Let RR_ij be the daily precipitation amount on day i in period j. Count the number of days where: RR_ij ≥ 10mm

R20mm

Annual count of days when PRCP≥ 20mm

Let RR_ij be the daily precipitation amount on day i in period j. Count the number of days where: RR_ij ≥ 20mm

Rnnmm

Annual count of days when PRCP≥ nnmm, nn is a user defined threshold

Let RR_ij be the daily precipitation amount on day i in period j. Count the number of days where: RR_ij ≥ nnmm

CDD

Maximum length of dry spell, maximum number of consecutive days with RR < 1mm

Let RR_ij be the daily precipitation amount on day i in period j. Count the largest number of consecutive days where: RR_ij < 1mm

CWD

Maximum length of wet spell, maximum number of consecutive days with RR ≥ 1mm

Let RR_ij be the daily precipitation amount on day i in period j. Count the largest number of consecutive days where: RR_ij ≥ 1mm

R95pTOT

Annual total PRCP when RR > 95p

Let RR_wj be the daily precipitation amount on a wet day w (RR ≥ 1.0mm) in period i and let RR_wn95 be the 95^th percentile of precipitation on wet days in the 1961-1990 period. If W represents the number of wet days in the period, then:

$R95p_{j}=∑↙{w=1}↖W RR_{wj}$ where $RR_{wj} > RR_{wn}95$

R99pTOT

Annual total PRCP when RR > 99p

Let RR_wj be the daily precipitation amount on a wet day w (RR ≥ 1.0mm) in period i and let RR_wn99 be the 99^th percentile of precipitation on wet days in the 1961-1990 period. If W represents the number of wet days in the period, then:

$R99p_{j}=∑↙{w=1}↖W RR_{wj}$ where $RR_{wj} > RR_{wn}99$

PRCPTOT

Annual total precipitation in wet days

Let RR_ij be the daily precipitation amount on day i in period j. If I represents the number of days in j, then

$$PRCPTOT_{j}=∑↙{i=1}↖{I} RR_{ij}$$