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Summer precipitation anomaly over the Southern Qinghai Plateau and related regions of

atmospheric water vapor transport

REN Yu1,2 ZHANG Xue-qin1 TAO Jie (Reporter)1,2 LI Sheng-chen3

1. Institute of geopraphical sciences and natural resources research, Beijing, China

2. Graduate university of Chinese Academy of Sciences, Beijing, China

3. Qinghai Meteorological Administration, Xining, China

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Outline

• Introduction

• Data & Method

• Results

• Conclusion

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Outline

• Introduction

• Data & Method

• Results

• Conclusion

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89° E 90° E 91° E 92° E 93° E 94° E 95° E 96° E 97° E 98° E 99° E 100° E 101° E 102° E 103° E

32° N

33° N

34° N

35° N

36° N

Q inghai

T ibet

Great threat

Introduction

Stabilization of water resources

Varied mountainous

topography

Elevation about 4,400m.a.s.l

Three Rivers Source (the

Yangtze River, Yellow River,

Lancang River)

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Introduction

Research points:

1. Identify the main modes of spatial distribution of precipitation anomaly over SQP (Southern Qinghai Plateau)

2. The correlated regions of atmospheric water vapor transport

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Outline

• Introduction

• Data & Method

• Results

• Conclusion

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Data & Method

89° E 90° E 91° E 92° E 93° E 94° E 95° E 96° E 97° E 98° E 99° E 100° E 101° E 102° E 103° E

32° N

33° N

34° N

35° N

36° N

Yellow R iverYangtze R iver

Langcang R iver

Summer (JJA) precipitation data of 19 surface meteorological stations from 1961-2004, supplied by Qinghai Climate Center

Summer holds the most part of the annual precipitation over SQP

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Data & Method

2.5o×2.5ogrid data of surface pressure, specific humidity, U-wind & V-wind from NCEP/NCAR Reanalysis (1961-2004)

60 70 80 90 100 110 120 130 140 150

10

20

30

40

50

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Vertically integrated water vapor flux vector( ), and its component , are calculated according to [Li, 1999]

Data & Method

Q

Q QPrecipitation anomaly modes and time coefficient (TC) Series (by EOF)

Pearson correlation between the TC series and , of both spring (MAM) and summer (JJA)

LI, W. P. Moisture Flux and Water Balance over the South China Sea during Late Boreal Spring and Summer,Theoretical and Applied Climatology, 1999: 64, p179-187.

Related regions of water vapor transport

Q Q

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Outline

• Introduction

• Data & Method

• Results

• Conclusion

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Results: The distribution of mean summer precipitation

Decrease from the southeast to the northwest

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Results: The three modes of summer precipitation over SQP

19611965 1970 1975 1980 1985 1990 1995 20002004-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

Year

Tim

e c

oeff

icie

nt

34.4%

•Spatial homogeneous•Anomalies decrease from the southeast to the northwest

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Opposite precipitation anomaly at the eastHuangnan TAP to the south Yushu TAP

Results: The three modes of summer precipitation over SQP

19611965 1970 1975 1980 1985 1990 1995 20002004-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

Year

Tim

e c

oeff

icie

nt

22.6%

TAP: Tibetan Autonomous Prefecture

1419611965 1970 1975 1980 1985 1990 1995 20002004-3

-2

-1

0

1

2

3

Year

Tim

e c

oeff

icie

nt

Results: The three modes of summer precipitation over SQP

9.9%

Opposite anomaly over the south Guoluo TAPto the northern SQP

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Results: Water vapor transport

Strong northeastward moisture transport over South China

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Results: Water vapor transport

Strong water vapor transport from the Arab Sea and the Bay ofBengal, the central South China Sea and the West Pacific Ocean

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Results: related regions for mode I

34.4%

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Results: Related water vapor transport regions

Spring Q Spring Q

The most significant correlated region is the central South China Sea

(When the northward water vapor transport is stronger, the SQP experiences a rainy summer)

Mode I

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Results: Related water vapor transport regions

Summer Q Summer Q

The most significant correlated region is the West Siberia

(When the eastward water vapor transport is stronger, the SQP suffers less precipitation in summer)

Mode I

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22.6%

Results: related regions for mode II

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Results: Related water vapor transport regions

Spring Q Spring Q

Not well correlated

Mode II

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Results: Related water vapor transport regions

Summer Q Summer Q

Mode II

The most significant correlated region is the eastward water vapor transfer band expanding along the Yangtze River from north Guizhou Province to East China Sea

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9.9%

Results: related regions for mode III

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Results: Related water vapor transport regions

Spring Q Spring Q

Mode III

The eastward water vapor transport over the northwestern part of Mongolia, the southward transport over north Xinjiang Uygur Autonomous Region of China, the northward transport

over the sea to the northeast of Pilipino are correlated with TC series III.

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Results: Related water vapor transport regions

Summer Q Summer Q

Mode III

The most significant correlated region is found in central Mongolia People’s Republic

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Outline

• Introduction

• Data & Method

• Results

• Conclusion

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Conclusion

Mode I: Spatial homogeneous Northward transport, South China Sea, Spring Eastward transport, West Siberia, Summer

Mode II: Opposite (East Huangnan TAP: South Yushu TAP) Eastward transport band expanding along the Yangtze River from the north Guizhou province to East China Sea, Summer

Mode III: Opposite (South Guoluo TAP: Northern part of SQP Northward water vapor transport over Mongolia, Summer

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