Earth's climates defined with respect to patterns of long-term averages
of the elements
Most important of these elements: temperature and precipitation
TEMPERATURE
Most important aspects: mean monthly, esp
Jan and July temperature range, annual temperature range; also
used in climate descriptions: daily max and min and
their average
Controls
1. Insolation
2. Continentality
(land-water differences)
3. Elevation
and topography
4. Ocean surface
temperatures
(note importance
of atmospheric circulation in each of these)
Other important aspects (as climatic descriptors):
Temperature
Lag: greatest/least where? why?
Diurnal range
of temperature, importance of daily sun angle variation
Annual range
of temperature
Isanomalies
of temperature
Applied aspects
Frequency of
occurrence of days above or below threshold values, e.g.,
32F, 90F
Mean dates of
first and last "frost" and length of frost-free period
Heating and
cooling degree days
Variability
PRECIPITATION
Two aspects of importance: mean annual amount
and regime (annual distribution)
Controls
1. Temperature
2. Global convergence/divergence
patterns and their N-S shifting
3. Orography
4. Ocean surface
temperatures
5. Distance
from a moisture source/topographic blocking
Other important aspects
1. Mean number
of rain days
2. Intensity
(mostly for hydrologic purposes)
3. Rainfall
probabilities and return periods
4. Variability
DMD 11/95