《全球气候系统与气候变化》（英语版） 3 Atmospheric circulation

3 Global atmospheric circulation modes and variability

3 Global atmospheric circulation: modes and variability

3. 1 Mean conditions 3.2 Modes in atmospheric circulation 3.3 Changes in upper-level atmosphere 3. 4 Monsoon system

3.1 Mean conditions 3.2 Modes in atmospheric circulation 3.3 Changes in upper-level atmosphere 3.4 Monsoon system

General introduction

General introduction

ATMOSPHERIC VERTICAL STRUCTURE 120 110 Thermosphere 100 The troposphere(0-10 km) contains 80% of the atmospheric mass Mesopause Temperatures increase with altitude in the stratosphere(10-50 km) due to Mesosphere absorption of UV light by ozone(O3) There is limited excha of material 50 F-Stratopause between the troposphere and the Stratosphere 20 10 -Tropopause Troposphere 80-60-40-20020406080 Temperature(C)

ATMOSPHERIC VERTICAL STRUCTURE The troposphere (0 - ~10 km) contains ~80% of the atmospheric mass. Temperatures increase with altitude in the stratosphere (10 - 50 km) due to absorption of UV light by ozone (O3 ). There is limited exchange of material between the troposphere and the stratosphere

1 mb Above 99.9% Ideal gas law P=PRT ATMOSPHERIC PRESSURE 5mb Example: Above 99% 10mb-- T=15C=288K p=1.2 kg/m3 t-25 mb R=[287.05JK1kg1l A so mb 豆专 [1J=INm 10 Above 9o% p=1.013x105N/m2 Abore 50% =1013mb A敢,Evee 010030 500 70090 Pressure mb) Atmospheric pressure decreases rapidly with height. Climbing to an altitude of only 5.5 km, where the pressure is 500 mb, would put you above one-half of the atmosphere's molecules

ATMOSPHERIC PRESSURE Atmospheric pressure decreases rapidly with height. Climbing to an altitude of only 5.5 km, where the pressure is 500 mb, would put you above one-half of the atmosphere's molecules. Example: T= 15C = 288 K r = 1.2 kg /m3 R = [287.05 J K-1 kg-1 ] [1 J = 1 N m]  p = 1.013 x 105 N/m2 = 1013 mb Ideal Gas Law p =r R T

Height k Pressure (mb 100030 Stratosphere 20 50 1c0 000+……… Mt Everest Tropopause (23,028 10 3C0 Surface 850 Troposphere

Atmospheric circulation

Atmospheric circulation

Ascending Air Descending Air THERMALLY DIRECT CIRCULATION COLD WARM LOW ressure Pressure Descending Air Ascending Air THERMALLY INDIRECT WARM CIRCULATION COLD LOW Pressure Pressure

Descending Air High Pressure Ascending Air Low Pressure Descending Air High Pressure Ascending Air Low Pressure THERMALLY￾DIRECT CIRCULATION COLD WARM THERMALLY INDIRECT WARM CIRCULATION COLD

HADLEY CELL IS A THERMALLY-DIRECT CIRCULATION Equator

N Equator S HADLEY CELL IS A THERMALLY-DIRECT CIRCULATION

THERMALLY DIRECT CIRCULATION IN AN IDEALIZED NON-ROTATING EARTH

THERMALLY￾DIRECT CIRCULATION IN AN IDEALIZED NON-ROTATING EARTH