Max Min Temperature: Details
Field Descriptions
FREQUENCY: Code
Reporting frequency:
- H = hourly
- S = synoptic (3 hourly)
- D = daily
MAX_TEMP: degrees Celsius (deg C)
The highest temperature recorded in the period.
WARNING
It has been standard climatological practice to allocate the 0900 local time daily reading to the PREVIOUS DAY since 16 hours of the 24 hours relate to it. This will be the case for data output in the "Form 301" (F301) format that NIWA often provides. This is NOT the case for CliFlo output.
For CliFlo output the date/time of the measurement will be at the end of the period of measurement i.e. for a period of 24 hours, the maximum temperature will have occurred sometime in the 24 hours prior to the date/time in the "Date" column. (The database stores the data at the equivalent UTC time to the actual day and time of MEASUREMENT). See also the example below.
MAX_PERIOD: Hour
Length of time in which MAX_TEMP occurred.
MAX_RELIABILITY: "*"
Reliability; "*" if estimated else NULL.
ORIG_MAX_ORIGIN: Code
Source of maximum temperature data.
- D = Daily Climate
- S = Synop
- E = Environmental Data Recorder
- H = Clitel Hourly
MIN_TEMP: degrees Celcius (deg C)
The lowest temperature recorded in the period.
MIN_PERIOD: Hour
Length of time in which MIN_TEMP occurred.
MIN_RELIABILITY: "*"
Reliability; "*" if estimated else NULL.
ORIG_MIN_ORIGIN: Code
Source of minimum temperature data.
- D = Daily Climate
- S = Synop
- E = Environmental Data Recorder
- H = Clitel Hourly
GRASS_MIN: degrees Celcius (deg C)
The lowest temperature recorded over grass under standard conditions in the period.
GRASS_MIN_PERIOD: Hour
Length of time in which GRASS_MIN occurred.
GRASS_MIN_RELIABTY: "*"
Reliability; "*" if estimated else NULL.
ORIG_GRASS_MIN_O: Code
Source of grass minimum temperature data.
- D = Daily Climate
- S = Synop
- E = Environmental Data Recorder
- H = Clitel Hourly
MEAN_TEMP: degrees Celcius (deg C)
Mean temperature for period of mean.
MEAN_PERIOD: Hour
Length of time over which MEAN was calculated.
MEAN_RELIABILITY: "*"
Reliability; "*" if estimated else NULL.
ORIG_MEAN_ORIGIN: Code
Source source of MEAN data; .
MEAN_RH: Percent (%)
Mean Relative Humidity over period of mean.
Notes
- These four MEAN fields are reported at hourly frequencies by our CLITEL loggers, the first beginning in mid-1995.
- It was assumed that both Maximum Temp and Minimum Temp would give similar catalogue entries for availability, so only Maximum Temp has been cataloged.
- Catalogue entries for 03-08, 43, 44 and 61-63 are based on the MTHLY_STATS table, not the MAX_MIN_TEMP table.
- For case Frequency=H, period=1, origin E=Environmental Data Recorder:
- MAX - The highest air temperature reported in 6 10-min reports
- MIN - The lowest air temperature reported in 6 10-min reports
- GMIN- The lowest grass temperature reported in 6 10-min reports
- If less that 4 10-min reports in hour, then values rejected; and if 4 or 5 10-min reports in hour the reliability flagged as '*'
- For case Frequency=H, period=1, origin H=CLITEL logger:
- The CLITEL loggers in the field report to a PC. The CLImate TELephone data are then processed to create hourly records and Daily Climate records, which are passed to the database machine and updated in the early morning.
- In addition to the MAX, MIN, and GMIN sets, a MEAN set is reported by our CLITEL loggers, the first beginning in mid-1995.
- MEAN_TEMP - mean temperature for period of mean.
- MEAN_RH - mean Relative Humidity over the same period.
- For case Frequency=D, period=24, 48, etc, origin D=Daily Climate, S=Synop, CLITEL logger daily data handled as DLYCLI origin D:
- WARNING: It has been standard climatological practice to allocate the 0900 local time daily reading of the MAXIMUM to the PREVIOUS DAY since the Maximum is assumed to have occurred in the afternoon. The database stores this MAXIMUM at the UTC equivalent to the actual day and LOCAL time of MEASUREMENT. The MINIMUM and GRASS-MINIMUM are assumed to have occurred in the morning of the day and LOCAL time of measurement.
Statistics
Max/MIN statistics are compiled in MTHLY_STATS and ANNUAL_STATS for:
- Code 03: Mean Daily Maximum Air Temperature
- Code 04: Mean Daily Minimum Air Temperature
- Code 05: Mean Daily Grass Minimum Temperature
- Code 06: Extreme Daily Maximum Air Temperature (highest)
- Code 07: Extreme Daily Minimum Air Temperature (lowest)
- Code 08: Extreme Daily Grass Minimum Temperature (lowest)
- Code 43: Lowest Daily Maximum Air Temperature
- Code 44: Highest Daily Minimum Air Temperature
- Code 61,62,63 provide monthly stats for Std-Dev, lowest and highest Daily Mean temperatures.
- Code 22: Days of Ground Frost
- Code 23: Days of Screen Frost
Example
Max_min: Daily
| Station | Date (NZST) | Tmax(C) | Period (Hrs) | Tmin(C) | Period (Hrs) | Tgmin(C) | Period (Hrs) | Tmean(C) | RHmean (%) | Period (Hrs) | Freq |
| Reefton Ews | 30/12/05 8:00 | 24.8 | 24 | 12.1 | 24 | 9.1 | 24 | - | - | - | D |
| Reefton Ews | 31/12/05 8:00 | 21.3 | 24 | 16.2 | 24 | 13.4 | 24 | - | - | - | D |
| Reefton Ews | 1/1/06 8:00 | 24.7 | 24 | 9.8 | 24 | 5.7 | 24 | - | - | - | D |
| Reefton Ews | 2/1/06 8:00 | 21.8 | 24 | 13.5 | 24 | 11.7 | 24 | - | - | - | D |
Note: The maximum temperature of "24.7" against the date "1/1/06 8:00" occurred during the 24 hour period up to "1/1/06 8:00". (See also the warning under MAX_TEMP above).
See also:
Max Min Temperature
Screen Obs
Screen Obs: Details