Data Service / Atlas of Taiwan Climate Change Key Indices
Table 1 Climate change key indices used in this atlas
Temperature indices | Precipitation indices |
---|---|
DTR | RR1 |
TX90p | PRCPTOP |
TN90p | SDII |
TX10p | R10mm |
TN10p | R20mm |
TXx | R80mm |
TNx | R200mm |
TXn | Rx1day |
TNn | Rx5day |
HWDI | CDD |
CWDI | CWD |
Definitions of the indices for precipitation
- RR1, Wet days (units: days)
Annual count of days when daily precipitation ≥ 1mm - PRCPTOT, Annual total precipitation in wet days (units: mm)
- SDII, Simple daily precipitation intensity index (units: mm/day)
Annual total precipitation in wet days divided by the number of wet days - R10mm, Annual count of days when daily precipitation is greater than or equal to 10mm (units: days)
- R20mm, Annual count of days when daily precipitation is greater than or equal to 20mm (units: days)
- R80mm, Annual count of days when daily precipitation is greater than or equal to 80mm (units: days)
- R200mm, Annual count of days when daily precipitation is greater than or equal to 200mm (units: days)
- Rx1day, Annual Maximum 1‐day precipitation (units: mm)
- Rx5day, Annual maximum consecutive 5‐day precipitation (units: mm)
- CDD, Annual maximum number of consecutive dry days (units: days)
Annual maximum number of consecutive days with daily precipitation < 1mm - CWD, Annual maximum number of consecutive wet days (units: days)
Annual maximum number of consecutive days with daily precipitation ≥ 1mm
Definitions of the indices for temperature
- DTR, Daily temperature range (units: °C)
Annual mean difference between daily maximum temperature (TX) and daily minimum temperature (TN) - TX90p, Annual count of days when TX > 90th percentile (units: days)
Annual count of days when daily maximum temperature exceeds the 90th percentile of maximum temperature during a 5-day window centred on each calendar day of the baseline period 1995-2014. To avoid possible inhomogeneity across the in-base and out-base periods, the calculation for the baseline period (1995-2014) requires the use of a bootstrap processure. Details are described in Zhang et al. (2005). - TN90p, Annual count of days when TN > 90th percentile (units: days)
Annual count of days when daily minimum temperature exceeds the 90th percentile of minimum temperature during a 5-day window centred on each calendar day of the baseline period 1995-2014. To avoid possible inhomogeneity across the in-base and out-base periods, the calculation for the baseline period (1995-2014) requires the use of a bootstrap processure. Details are described in Zhang et al. (2005). - TX10p, Annual count of days when TX < 10th percentile (units: days)
Annual count of days when daily maximum temperature is below the 10th percentile of maximum temperature during a 5-day window centred on each calendar day of the baseline period 1995-2014. To avoid possible inhomogeneity across the in-base and out-base periods, the calculation for the baseline period (1995-2014) requires the use of a bootstrap processure. Details are described in Zhang et al. (2005). - TN10p, Annual count of days when TN < 10th percentile (units: days)
Annual count of days when daily minimum temperature is below the 10th percentile of minimum temperature during a 5-day window centred on each calendar day of the baseline period 1995-2014. To avoid possible inhomogeneity across the in-base and out-base periods, the calculation for the baseline period (1995-2014) requires the use of a bootstrap processure. Details are described in Zhang et al. (2005). - TXx, Annual maximum value of daily maximum temperature (units: °C)
- TNx, Annual maximum value of daily minimum temperature (units: °C)
- TXn, Annual minimum value of daily maximum temperature (units: °C)
- TNn, Annual minimum value of daily minimum temperature (units: °C)
- HWDI, Heat wave duration index (units: days)
Annual count of days with at least 3 consecutive days when TX > 95th percentile of the baseline period 1995-2014
Note: The original definition of heatwave (the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C) does not apply to the climate system in Taiwan, so it has been revised to be defined as daily maximum temperature with at least 3 consecutive days exceeds the 95th percentile during the baseline period (1995-2014). - CWDI, Cold wave duration index (units: days)
Annual count of days with at least 3 consecutive days when TN < 5th percentile of the baseline period 1995-2014
Note: In Taiwan, a cold wave is defined as the minimum temperature at Taipei Station being below 10°C. However, the original definition (the daily minimum temperature of more than five consecutive days is below the average minimum temperature by 5 °C) does not align with the commonly used definition in Taiwan, therefore it has been revised to be defined as daily minimum temperature with at least 3 consecutive days is below the 5th percentile during the baseline period (1995-2014).