Recent SST, Sea ice, and Snow Recent SST, Sea ice, and Snow Cover Monitoring and DiagnosisCover Monitoring and Diagnosis

Beijing Climate Center, CMA

YUAN Yuan, ZHOU Bing

（ Thanks to Dr. Guo Y J and Dr. Ma L J ）

1. Recent SST monitoring and diagnosis

2. Possible impacts of negative PDO

3. Sea ice and snow cover monitoring

Outline

Jan. 2013

Monthly SSTA

Feb. 2013

Dec. 2012

SSTA & OLR in DJF 2012/13

Anomaly percentage of rainfall in DJF

2012/13

A

Atmospheric Circulation Anom. DJF

Red contour: Climatological WPSH

Wang et al. 2000, J. Climate, 13: 1517-1536

ColdAWarmC

A

Physical Mechanism for the Anticyclone

e.g. Watanabe and Jin, 2002; Xie et al. 2009; Wu et al. 2010; Yuan et al, 2012

SSTA in March 2013

The latest weekly SST departures are:

Niño 4 0.0ºC

Niño 3.4 0.1ºC

Niño 3 0.0ºC

Niño 1+2 -0.9ºC

(From CPC)

1. Recent SST monitoring and diagnosis

2. Possible impacts of negative PDO

3. Sea ice and snow cover monitoring

Outline

Composite difference of summer rainfall anomaly between positive

and negative PDO years

NE NC JH YR SC

PDO 0.13 -0.2 -0.05 0.09 0.007

Precipitation data: GPCC V6 & CRU TS 3.10.01

NE9 NC9 JH9 YR9 SC9

PDO9 0.13 -0.68 0.02 0.36 0.08 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-1.5

-1

-0.5

0

0.5

1

1.5(a)

年份

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000-1.5

-1

-0.5

0

0.5

1

1.5(b)

年份

Red line: PDO9

Green and black lines: NC9

Composite Difference between positive and negative PDO phases

SSTA 850UV

500H

Negative PDONegative PDOEnhanced EASMEnhanced EASM

Eastward and northward WPSH

Eastward and northward WPSH

More summer rainfall in North

China

More summer rainfall in North

China

1. Recent SST monitoring and diagnosis

2. Possible impacts of negative PDO

3. Sea ice and snow cover monitoring

Outline

Sea Ice Concentration in NH--DJF

Over 40% below normal in the Barents Sea and western Kara Sea

The fourth least since 1978

Sea Ice Concentration in SH--DJF

Snow Cover Days in NH--DJF

Average Snow Depth in China--DJF

China

Northeast China

Northern Xinjiang

Tibet Plateau

Conclusions1. In DJF 2012/13, SSTA over the equatorial eastern-central Pacific was

slightly below normal; PDO persisted in its negative phase; SSTA over the tropical Indian Ocean was significantly above normal, which excited anomalous low-level anticyclone to the east of the Philippines

2. The significant negative PDO would lead to a strong East Asian summer monsoon and a weak WPSH in summer 2013. Therefore, more precipitation tends to occur in North China.

3. In DJF 2012/13, sea ice concentrations were over 40% below normal in Barents Sea and western Kara Sea, while mostly above normal in the sea areas around Antarctica.

4. The area of snow cover was evidently larger than normal in Northeast China, with the average snow depth the deepest since 1973.

Thank You!