Page 320 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

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part II The Water, Weather, and Climate Systems ITCZ
60.2
55.9
54.7
▼Figure 10.4 Tropical monsoon climate. [(b) shaileshnanal/Shuttershock.]
Subtropical high
36.8
Subtropical high
Station: Yangon, Myanmar* Lat/long: 16° 47′ N 96° 10′ E Avg. Ann. Temp.: 27.3°C Total Ann. Precip.: 268.8 cm Elevation: 23 m
Population: 6 000 000
Ann. Temp. Range: 5.5 C° *(Formerly Rangoon, Burma)
MYANMAR
Sittwe Yangon
INDIAN OCEAN
0 500 KILOMETRES
35.0 32.5 30.0 27.5 25.0 22.5 20.0 17.5 15.0 12.5 10.0
7.5 5.0 2.5
38
32
27
21
16
10
4
0
–1 –7
–12 –18 –23 –29 –34 –40
Equator
20°
20°
10° 10°
90° 100° 110°
Precipitation (cm)
Temperature (°C)
0
JFMAMJJASOND
Month
(a) Climograph for Yangon, Myanmar (formerly Rangoon, Burma); city of Sittwe also noted on map.
mesothermal Climates (midlatitudes, mild winters)
Mesothermal, meaning “middle temperature,” describes these warm and temperate climates, where true seasonality begins. More than half the world’s population resides in mesothermal climates, which occupy about 27% of Earth’s land and sea surface—the second largest percentage behind the tropical climates.
The mesothermal climates, and nearby portions of the microthermal climates (cold winters), are regions of great weather variability, for these are the latitudes of greatest air mass interac- tion. Causal elements include:
• latitudinal effects on insolation and temperature, as summers transition from hot to warm to cool moving poleward from the tropics;
• Shifting of maritime and continental air masses, as they are guided by upper-air westerly winds;
• Migration of cyclonic (low-pressure) and anticyclonic (high- pressure) systems, bringing changeable weather conditions and air mass conflicts;
• effects of sea-surface temperatures on air mass strength: Cooler temperatures along west coasts weaken air masses, and warmer temperatures along east coasts strengthen air masses.
(b) Mixed monsoonal forest and scrub characteristic of the region in eastern India.
San Francisco,
CA Bluefield, WV
Columbia, SC
Humid subtropical
Chengdu, China
Dunedin, New Zealand
Mesothermal climates are humid, except where subtropical high pressure produces dry-summer conditions. Their four distinct regimes based on precipitation variability are humid subtropical hot-summer (moist all year), humid subtropical winter-dry (hot to warm summers, in Asia), marine west coast (warm to cool sum- mers, moist all year), and Mediterranean dry-summer (warm to hot summers).
Marine west coast Mediterranean dry summer