CLIMATOLOGY OF CHINA AUTUMN

CLIMATOLOGY OF CHINA GEOGRAPHICAL LOCATION SEASONS TRANSIENT DISTURBANCES PRECIPITATION AVIATION WEATHER HAZARDS

CHINA – TERRAIN MAP

CHINA – POLITICAL (INTERNAL) MONGOLIAN BORDERLANDS NE CHINA MONGOLIAN BORDERLANDS NORTHWEST NORTH CHINA TAR SOUTH CHINA

SEASONS OF CHINA WINTER - DEC - FEB SPRING - MAR - MAY SUMMER - JUN - AUG AUTUMN - SEP – NOV "MAI-YU" - APR - JUNE "CRACHIN" - FEB - APR

DURATION OF THE SEASONS (MONTHS) REGION / SEASON SPRING SUMMER AUTUMN WINTER NORTH WEST CHINA 2-3 2 5-6 NORTH CHINA 1.5-3 2-4.5 1.5-2 4.5-6 CENTRAL CHINA 3-5 2.5-4.5 SOUTH CHINA 4-6 6-8 -

AUTUMN A PERIOD OF FINE AND COMFORTABLE WEATHER CRISP AIR, BRIGHT SUNSHINE AND GENTLE BREEZES HIGH TEMPERATURES PERSIST IN SEP THIS HOT AND UNCOMFORTABLE WEATHER IS KNOWN AS TIGER WEATHER OCCASIONALLY PROLONGED RAINS OVER LOWER YANGTZE RIVER, UNDER INFLUENCE OF FREQUENT TYPHOONS AND TROPICAL DEPRESSIONS

NORTH EAST MONSOON ATTRIBUTED TO COLD AIR AND HIGH PRESSURE AREA OVER ASIAN CONTINENT HOT WX REPLACED BY MILD CONDITIONS WINDS TURNING FROM SW –SE’LIES TO NE-N’LIES CAN AFFECT TROPICAL CYCLONES OVER SOUTH CHINA SEA IF NE MONSOON MEETS WARM & MOIST AIR OF TROPICAL CYCLONES, WINDY AND RAILNY WX FOLLOWS, CALLED “WET COLD DEW WIND” IN MAINLAND CHINA INTERVAL BETWEEN TWO WCDW IS 6-8 DAYS

TROUGH IN WESTERLIES EXTRA TROPICAL CYCLONES & ANTICYCLONES TYPHOONS DISTURBANCES TROUGH IN WESTERLIES EXTRA TROPICAL CYCLONES & ANTICYCLONES TYPHOONS

TROUGHS IN THE WESTERLIES MOST OF THE AREA STAYS UNDER WESTERLY WIND REGIME TROUGHS AND RIDGES WITH VARYING AMPLITUDE MOVE ACROSS CHINA AVERAGE SPEED OF PROPAGATION 10-15O LONGITUDE PER DAY ENHANCE RAINFALL IN THE NORTH AND AT TIMES TO THE CENTRAL PARTS OF CHINA

EXTRA TROPICAL CYCLONES & ANTICYCLONES MAXIMUM INTENSITY IN JUNE. PATHS COVER UP TO CENTRAL CHINA IN WINTERS THE EXTRA TROPICAL ANTICYCLONES ORIGINATE IN SIBERIA AND MONGOLIA DURING WINTERS (CRACHIN) GENERAL DIRECTION OF MOVEMENT E-SE WARDS

TYPHOONS FROM CHINESE WORD ‘TEI FUNG’ MEANING ‘BIG WIND’ INTENSE TROPICAL STORMS, ORIGINATE IN NW PACIFIC, MAXIMUM 4-6 PER MONTH, DURING JULY TO OCTOBER PRACTICALLY NIL TYPHOONS FORM BETWEEN DECEMBER TO APRIL ASSOCIATED WITH STRONG WINDS AND HEAVY RAINFALL IN SOUTHEAST AND NORTH CHINA. ACCOUNTS FOR > 50% OF ANNUAL RAINFALL IN THE COASTAL REGIONS DOES NOT PERSIST FOR MORE THAN 500 KM INLAND FROM THE COAST

TYPHOON STATISTICS MONTH DEPRESSION TYPHOON D + TY JAN 0.2 0.5 0.7 FEB 0.4 0.6 MAR 0.1 APR 0.8 MAY 1.1 1.2 JUN 2.0 2.7 JUL 1.4 4.4 5.8 AUG 2.3 6.1 8.4 SEP 1.8 5.3 7.1 OCT 3.8 4.6 NOV 3.1 DEC 1.3 1.7 Total (Year) 8.5 28.8 37.3

8-10 TYPHOONS IN A YEAR WITH MAX PROBABILITY IN JULY TYPHOON STATISTICS COUNTRY/ MONTH(S) PERCENTAGE OF TYPHOON STRIKES EXPERIENCED BY COUNTRIES IN NW PACIFIC (1949-76) JAN-MAY JUNE JULY AUGUST SEPT OCT NOV-DEC YEAR CHINA 25 38 48 39 40 19 16 35 PHILIPPIN-ES 66 24 13 8 31 60 21 JAPAN 6 22 20 28 11 1 VIETNAM 9 36 23 15 KOREA 3 7 USSR 2 4 ON AVERAGE 8-10 TYPHOONS IN A YEAR WITH MAX PROBABILITY IN JULY

PRECIPITATION

ANNUAL VARIATION SEASON MONTHS CLIMATE JAN WINTER NOV –FEB DRY & COLD SUMMER JUN – AUG RAINY MAY TRANSITIONAL MONTHS SEP JAN N CHINA EXPERIENCES VERY DRY WX PERSISTENTLY CLEAR SKIES RAINFALL AMOUNT > 50 MM NE & NW CHINA, MONGOLIAN BORDERLANDS RECEIVES RF/SF BETWEEN 50 – 100MM JULY PRECIPITATION VARIABILITY IS MORE N, S AND NE CHINA RECEIVE RF BETWEEN 150 – 200 MM NW CHINA RECEIVE < 25 MM SPRING APRIL N & S CHINA RECEIVES > 100 MM TIBET, NW CHINAAND MONGOLIAN BORDERLANDS < 25 MM AUTUMN OCT N AND S CHINA RECEIVES <50 MM NW < 10 MMAND NE < 50 MM

CHINA – RIVER BASINS > 50 MM QIN LING, HUAIHE YANGTSE TAIWAN, HAINAN ISLAND, GUANGDONG 1750 -2000MM

CHINA – TEMPERATURE

AVIATION WEATHER HAZARDS

DUST STORMS MOST FAVOURABLE AREAS : PLAINS OF NORTH CHINA AND SOUTH MANCHURIA THE MAIN SEASON OF OCCURRENCE IS FROM MARCH TO MAY AND JULY TO SEPTEMBER MOST FAVOURABLE SITUATION IS PASSAGE OF THE FRONTS THE MOST LIKELY TIME OF OCCURRENCE IS NOON TO EVENING

FOG ADVECTION FOG IS COMMON IN SUMMERS, RADIATION TYPE IN WINTERS MAXIMUM AT NIGHT, STAYS TILL AROUND 0700 H IN THE MORNING. IN JAN, PERSISTS TILL NOON OVER LAND AREAS. THE FAVOURABLE AREAS : SOUTH CHINA HILLS AND SICHUAN BASIN. (186 DAYS PER YEAR) FREQUENCY OF <5 DAYS OVER QINGHAI-XIZANG AND XINJIANG FREQUENCY OF 5- 25 DAYS PER YEAR OVER COASTAL REGIONS

THUNDERSTORM MOST FAVOURABLE REGIONS ARE HAINAN AND LUICHOW PENINSULA WITH FREQUENCY 90-100 PER YEAR DURING MAR-SEP FREQUENCY DECREASES TO ABOUT 10 NE-WARDS TO HEILUNGKIANG FREQUENCY 30 DAYS OVER SOUTHERN PROVINCES FREQUENCY ABOUT 5 IN THE DESERTS AND 20 IN THE HILLS

HAIL OCCURS JUST ONCE OR TWICE PER YEAR OVER YUNNAN (SOUTH CHINA), OTHERWISE PRACTICALLY UNKNOWN IN THE PLAINS 4-5 HAILSTORMS PER YEAR OVER THE NORTH CHINA PLAINS AT ALTITUDE MORE THAN 1000 M ATLEAST 6 HAILSTORMS PER YEAR OVER KANSU IN NORTHWEST CHINA AT LEAST 5-7 HAILSTORMS PER YEAR OVER SHENSI (NORTH CHINA)

CONCLUSION