1. Climate in China

In June 2014, the surface air temperature averaged over China was 20.5ºC, which was 0.5ºC above normal (20.0ºC). The mean precipitation over China was 100.7 mm, which was slightly above normal (99.3mm). In the month, extremes of High Temperature (HT), Daily Precipitation (DP), Consecutive Precipitation (CP) and Consecutive Precipitation Days (CPD) were observed in China.

2. General Circulation Features

Northern Hemisphere: During June 2014, in the 500hPa geopotential height anomaly field, positive anomalies above 4 dam covered regions from central Russia to northwestern North Pacific Ocean via southern Okhotsk and from Norwegian Sea to northeastern Canada by way of southern Greenland, with central values above 8 dam near the south Greenland Sea. Meanwhile, negative anomalies below -4 dam covered Alaska and mid-western North America. For the month, the northwestern Pacific subtropical high was weaker than normal, with its area smaller than normal and its high ridge extending more southward and slightly eastward.

Southern Hemisphere: For the month, in the 500hPa geopotential height anomaly field, positive anomalies over 4 dam were observed over southwestern South Atlantic, southern South Pacific and northeastern South Indian Ocean, with central values above 12 dam in locals of South Pacific. Meanwhile, negative anomalies below -4 dam mainly covered the region from southeastern South Atlantic Ocean to Southwest Indian Ocean, southern Southeast Pacific Ocean to Ross Sea via West Antarctica and some parts of middle and eastern East Antarctica, with central values below -12 dam.

3. Tropical Features

Sea Surface Temperatures (SSTs): During June 2014, SST anomalies were over 0.5℃ across the equatorial Pacific, especially above 1℃ to the east of 130ºW and above 2.5℃ along the coastal areas of South America. Indices of Niño1+2、Niño3、Niño4、Niño3.4 and Niño Z were 1.8℃, 0.9℃, 0.6℃, 0.5℃ and 0.9℃, respectively. SSTs were over 0.5℃ above normal in the South China Sea and near normal across the tropical Indian Ocean. The IOBW index was 0.3℃. SSTs were below normal in the most of North Atlantic Ocean. The North Atlantic SST tripole was keeping the positive phase.

Subsurface Temperatures: During June 2014, anomalously warm subsurface water weakened rapidly and shifted east, upwelling to the surface in the eastern equatorial Pacific, while anomalously cold subsurface water persisted in the central and east-central Pacific at depth (100~400 m).

Warm Pools: For the month, the areas of both Indian Ocean and the western Pacific warm pools were slightly larger than normal. And their intensities were both above normal significantly.

Wind Field: For the month, at lower troposphere (850hPa), westerly anomalies covered the most equatorial Pacific and equatorial Indian Ocean, with central values at least 8 m/s. At upper troposphere (200hPa), easterly anomalies dominated over most equatorial Pacific, with central values above 8 m/s, while westerly anomalies were observed over the equatorial Indian Ocean and the Marine continent.

Southern Oscillation: For the month, the Southern Oscillation Index (SOI) was 0.

Convections over the Tropics: During June 2014, the anomalous outgoing longwave radiation (OLR) showed that convection was near normal over most tropical oceans. However, convection was enhanced in the vicinity of the date line over tropical Pacific and the mid-north of the South China Sea with central values below -30W/m². Meanwhile, convection was suppressed to the west of Sri Lanka over the tropical Indian Ocean.

4. ENSO Monitoring and Outlook

Sea surface temperature (SST) in the middle-western equatorial Pacific decreased and SST nearby the dateline was near the average. Because a weak Kelvin wave has propagated eastward from May to June, 2014, SST in the middle-eastern equatorial Pacific increased continually and the abnormal warm water extended to 150°W. The index of NINO Z still remain above 0.5℃. The thermocline was deeper than normal and remained warm phase of Tilt mode. Discharge process started over equator. The SST of basin scale will decrease .

Based on the dynamical model prediction and the diagnostic analysis, the SST will increase in the middle-eastern equatorial Pacific in the following months. A moderate strength El Nino event is expected.

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