1. Climate in China

In February 2014, the surface air temperature averaged over China was -2.3ºC, which was 0.6ºC below normal (-1.7ºC). The mean precipitation over China was 17.5 mm, which was near normal (17.4mm). In the month, the extremeevents of Daily Minimum Temperature (DMT), Daily Temperature Drop (DTD)and Consecutive Temperature Drop (CTD)were observed in China.

2. General Circulation Features

Northern Hemisphere: During February 2014, in the field of mean 500hPa geopotential height anomaly, positive anomalies above 4 dam covered polar region, central North Atlantic Ocean, regions from eastern Europe to western North Pacific, and southeastern North Pacific. Meanwhile, negative anomalies below-4 dam covered regions from central North America to northern North Atlantic Ocean, and central Russia. During the month, the northwestern Pacific subtropical high was weaker than normal, with the area smaller than normal. The position of the northwestern Pacific subtropical high shifted further eastward and southward than normal.

Southern Hemisphere: For the month, in the field of mean 500hPa geopotential height anomaly, positive anomalies over 4 dam were observed over southern South Pacific, negative anomalies below -4 dam were observed over southern South Atlantic Ocean, and the regions near Antarctic Peninsula.

3. Tropical Features

Sea Surface Temperatures (SSTs): During February 2014, SSTs were about 0.5℃ above normal over the western equatorial Pacific, about 0.5℃ below normal over most central-eastern equatorial Pacific. Niño1+2, Niño3, Niño4, Niño3.4 and NiñoZ indices were -0.8℃, -0.8℃, 0.3℃, -0.5℃ and -0.3℃, respectively. SSTs were slightly below normal over the northern tropical Indian Ocean, and over 0.5℃ above normal over most southern subtropical Indian Ocean. The Indian Ocean basin-wide index was 0℃. SSTs were near normal over the tropical Atlantic Ocean.

Subsurface Temperatures: During February 2014, anomalously warm subsurface water dominated in the western equatorial Pacific, with the central value above 5℃ near 175ºW. Meanwhile, anomalously cold subsurface water controlled most central-eastern equatorial Pacific, with the central value below -3℃ in the eastern equatorial Pacific near 115ºW.

Warm Pools: For the month, the area of both Indian Ocean and western Pacific warm pools was slightly larger than normal, with the intensity of the Indian Ocean warm pool slightly above normal and that of the western Pacific warm pool significantly above normal.

Wind Field: For the month, at lower troposphere (850hPa), anomalous westerly winds covered the equatorial Indian Ocean, most western equatorial Pacific, and the central-eastern equatorial Pacific. The eastern equatorial Pacific was controlled by weak anomalous easterly winds. At upper troposphere (200hPa), westerly wind anomaliesdominated over the most equatorial Pacific, with the central value above 12 m/s. Weak easterly anomalies controlled theequatorial Indian Ocean.

Southern Oscillation: For the month, the Southern Oscillation Index (SOI) was -0.1.

Convections over the Tropics:During February 2014, the anomalous outgoing longwave radiation (OLR) showed that convection was active over the western equatorial Indian Ocean and western equatorial Pacific, with the central value below -15W/m². However, inactive convection controlled the eastern equatorial Indian Ocean and the central equatorial Pacific. Convection was above normal over most tropical Atlantic Ocean, with the central value below -15W/m².

4. ENSO Monitoring and Outlook

At present, ENSO-neutral with slightly coldcondition continues.However, the positive anomaly of the subsurface Pacific heat content has been increasing substantially since mid-February 2014, associated with subsurface warm water extending eastwards and its center shifting to the east of dateline. Furthermore,westerly anomaliesat 850-hPa level have dominated the central equatorial Pacific since February 2014.All the above changeswill likely warmthe sea surface temperature of the Nino regions in the coming months.

Almost all the models indicate that ENSO-neutralwill persist through the rest of the Northern Hemisphere spring 2014. While all models predict warming in the tropical Pacific, there is considerable uncertainty as to whether El Niño will develop during the summer or fall. Therefore, it is concluded that ENSO-neutral with slightly warm conditions is expected to go through the next 3 months (April to June).

Therefore, we will closely monitor the development of ENSO conditions and update our ENSO wrap-up in time.