1. Climate in China

In July 2014, the surface air temperature averaged over China was 22.3ºC, which was 0.4ºC above normal (21.9ºC). The mean precipitation over China was 115.0 mm, which was slightly below normal (120.6mm). 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 July 2014, in the 500hPa geopotential height anomaly field, the positive anomalies above 4 dam covered Europe, near the Aleutian Islands and northern North Atlantic Ocean.

Meanwhile, the negative anomalies below -4 dam covered western Russia, central North Pacific and northern North America. For the month, the northwestern Pacific subtropical high was weaker than normal, and its area was near the normal. And, its position shifted further westward than normal.

Southern Hemisphere: For the month, in the 500hPa geopotential height anomaly field, the positive anomalies over 4 dam were observed over southern South Atlantic and southern South Pacific.

Meanwhile, the negative anomalies below -4 dam mainly covered southwestern Pacific Ocean and South Indian Ocean.

3. Tropical Features

Sea Surface Temperatures (SSTs): During July 2014, SSTs were over 0.5℃ above normal in most equatorial central-eastern Pacific, especially above 1℃ to the east of 120ºW . Indices of Niño1+2、Niño3、Niño4、Niño3.4 and Niño Z were 1.3℃，0.7℃，0.3℃，0.2℃ and 0.6℃, respectively. SSTs were over 0.5℃ above normal in most equatorial western Pacific. The IOBW index was 0.2℃. The North Atlantic SST tripole kept the positive phase.

Subsurface Temperatures: During July 2014, anomalously cold subsurface water persisted in the central-eastern Pacific at depth (50~250 m), while anomalously warm subsurface water enhanced and extended eastward in the equatorial western Pacific.

Warm Pools: For the month, the area of Indian Ocean warm pool was near normal, the area of western Pacific warm pool was larger than normal. And their intensities were both above normal significantly.

Wind Field: For the month, at lower troposphere (850hPa), westerly anomalies dominated most equatorial Pacific, with central values above 6 m/s. At upper troposphere (200hPa), westerly anomalies covered the equatorial eastern Pacific, with central values above 8 m/s, while easterly anomalies controlled the region from the Marine continent to the equatorial central Pacific, with central values below -8 m/s.

Southern Oscillation: For the month, the Southern Oscillation Index (SOI) was -0.3.

Convections over the Tropics: During July 2014, the anomalous outgoing longwave radiation (OLR) showed that convection was active over most tropical Pacific, with central values below -30W/m². However, convection was suppressed over most tropical Indian Ocean, with central values above 15W/m².

4. ENSO Monitoring and Outlook

At present, the response of the tropic atmosphere to the El Niño was weak and there was no obvious positive feedback between them. The equatorial subsurface ocean status implied that another warming was occurring in the central and eastern equatorial Pacific Ocean in September. The Sea surface temperature (SST) was expected increased a little more than the SST in the end of the July due to the weak process. The SST in the central and eastern equatorial Pacific Ocean remained warm and the El Niño status maintained. Based on the dynamical model prediction and the diagnostic analysis, the probability of a moderate intensity El Niño event occur in fall was reduced and the likelihood of weak El Nino event was increasing.

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