Representing Climate Data Part I Maps and Numbers Representing Climate Data

Station Models Isoline Maps Satellite Images

Station model: an abbreviated plot of weather station data

Station model: abbreviation of weather station data

Current weather map

Station model: (p. 411, textbook) Pressure (without decimal point; without initial 10 or 9)(mb) Air Temperature Cloud cover pressure change in past 3 hrs (without decimal pt) Present weather Dew point Wind direction Wind speed

Wind direction Direction arrow points is wind direction (direction wind is coming FROM) If calm, no arrow and double circle

Wind speed

“knot” Nautical mile per hour 1 knot = 1.15 mph; 1.9 km/hr

Current pressure 162 = 1016.2 mb 3 numbers; in mb; no decimal point; 10 or 9 at beginning of number is NOT shown 162 Does number begin with “10” or “9” ? 162 = 1016.2 mb

353 ? 1035.3 mb 175? 1017.5 mb 985? 998.5 mb 893? 989.3 mb 074? 1007.4 mb 890? 989 mb

Pressure tendency during past three hours Amount of change; mb; No decimal shown; 02

07 13

Current surface analysis

Isoline maps Interpolate between discrete data points to create a continuous “surface”: Helps us to visualize the data examples: Elevation surface Pressure surface Temperature surface

Topographic map an elevation surface Contour lines

Temperature map 20 30 isotherms 40 50 50 60

Isotherm map

Pressure surface isobars

All data values on an isoline are equal. The interval between lines is constant for the entire map. 50 40 52 45 50 39 60 43 60 70 64 69 58

Trough: line of relatively low values (Isolines point to higher values) Ridge: line of relatively high values (Isolines point toward lower values) Terms usually used on pressure maps

Isotherm map

Current weather map

Gradient Steep/strong gradient: close isolines Weak gradient: widely spaced isolines

500 miles H L 1004 1020 1006 1008 1010 1018 1014 1012 1016