Term Assignment #1

• To analyze the spatial and temporal distribution of precipitation in southwestern Saskatchewan

• format of monthly records of daily data:
  
  station id (7 digits) year (3; e.g. 987) month (2) element (3)¹ sign (1)² value (5)³ flag(1)⁴

  ¹ rain = 010, snow = 011, total precipitation = 012

  ² positive = '0', negative = '- '

  ³ units of precipitation = 0.1 mm

  ⁴ T = trace, C = amount uncertain, F = accumulated and estimated, M = missing

  • the sign, value and flag are repeated up to 31 times (i.e. one observation per day); -99999 indicates missing data
    
    
  • for example, here are the daily maximum temperatures (element 001) for August (08), 1911 (911) at Yellow Grass (station 4019040):

    401904091108001000222 000233 000228 000239 000211 000200 000228 000200 000150 000194 000222 000239 000289 000294 000250 000206 000217 000222 000294 000289 000283 000150 000200 000206 000228 000194 000144 000144 000178 000194 000267

  • here are the daily precipitation data (element 012) for June (06), 1938 (938) at Swift Current (station 4028035):

    402803593806012000000 000041 000000T000000 000000 000000T000000 000198 000041 000003 000000 000000 000010 000000 000000 000015 000117 000020 000000 000000 000000 000000 000051 000000 000000 000000 000000 000000 000000 000005 -99999M

• Click here to download the file 327data.zip which contains all the daily precipitation data for the 34 stations. After you save this file (to a directory on your hard drive) and unzip it, there will be one file for each station. The file names consist of the first four letters of the station name plus _012. For example, the file abbe_012.dat contains the daily total precipitation data (element 012) for Abbey.

Instructions

1. Construct a map of southwestern Saskatchewan showing the locations of the climate stations (towns). Make three copies.
2. Compute total annual precipitation for each station for two different years. Put these data on two of the maps. Interpolate isohyets (lines of constant precipitation). Briefly describe the spatial distribution of annual precipitation and any differences between the two years.
3. In the database, find a storm that produced precipitation at all the weather stations. On the third map construct Thiessen polygons. Determine the area-weighted average precipitation from this storm.
4. Do one more analysis (among days, months, years, storms or stations) of your choice.

Table 1. Daily precipitation data for southwestern Saskatchewan

Table 2. Southwestern Saskatchewan Climate Stations