1. Climate in China

In March 2016, the surface air temperature averaged over China was 6.1ºC, with 2.0ºC above normal (4.1ºC). The mean precipitation was 29.3mm over China, which was near normal (29.5 mm). For the month, extremes of Daily Temperature Drop (DTD) and heavy precipitation were observed in China.

2. General Circulation Features

Northern Hemisphere: During March 2016, in the field of mean 500hPa geopotential height anomaly, positive anomalies above 4 dam covered the regions from Central Asia to the Sea of Okhotsk, parts of the polar region, northeastern United States and its adjacent seas, parts of northeastern Africa. Meanwhile, negative anomalies below -4 dam covered the northeastern North Pacific, northeastern North America and western Europe, with the central values below -12dam over northeastern North Pacific. During the month, the northwestern Pacific subtropical high was stronger than normal, with the area larger than normal. The west point of its extended ridge shifted far further westward than normal.

Southern Hemisphere: For the month, in the field of mean 500hPa geopotential height anomaly, positive anomalies over 4 dam were observed over the southern South Indian Ocean, the southwestern South Atlantic Ocean and parts of the southwestern South Pacific. Meanwhile, negative anomalies below -4 dam covered most of the Antarctica, southern South Africa and their adjacent waters, with the central values below -12dam over the Amundsen Sea.

3. Tropical Features

Sea Surface Temperatures (SSTs): In March 2016, SSTs were at least 0.5℃ above normal in most of the central and eastern equatorial Pacific, with central values at least 2℃ above normal. Indices of Niño1+2，Niño3，Niño4，Niño3.4 and Niño Z were 0.9℃，1.5℃，1.4℃，1.7℃ and 1.4℃, respectively. The Indian Ocean Basin-Wide SSTA variation index (IOBW) was 0.8. The North Atlantic Triple (NAT) index was 1.2.

Subsurface Temperatures: In the month, the anomalously warm subsurface water was located in the central-eastern equatorial Pacific, with the central values above 4.0℃, and the intensity was observed weaker than the last month. Meanwhile, the anomalously cold subsurface water strengthened in the western equatorial Pacific and shifted eastward, with central values below -4℃.

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

Wind Field: For the month, at lower troposphere (850hPa), the westerly anomalies dominated the equatorial Pacific from the vicinity of the date line to the east of it. Meanwhile, the easterly anomalies dominated the equatorial west Pacific. At upper troposphere (200hPa), the easterly anomalies prevailed over the central equatorial Pacific Ocean, while the westerly anomalies dominated the eastern equatorial Pacific east of 120°W, and the western equatorial Pacific west of 150°E to the equatorial Indian Ocean.

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

Convections over the Tropics: During the month, the anomalous outgoing long wave radiation (OLR) showed that convections were active over the equatorial Pacific region from the date line easterly to the equatorial western Pacific till 120°W, with central values below -45 W/m². Meanwhile, convections were suppressed over the r tropical West Pacific with central values above 30 W/m².

4. ENSO Monitoring and Outlook

The SST in the Nino regions has decreased to below 1.5℃ since March 2016. Meanwhile the subsurface SSTs in the whole equatorial Pacific below 50 meters have become colder than normal. Furthermore, the cold Kelvin waves in the equatorial Pacific are propagating eastward, which will weaken the El Niño event. As one of the results of the El Nino decaying, the anomalies of the upper-ocean heat content in the equatorial central-eastern Pacific have become into negative phase since mid-March 2016.

Based on the current monitoring of the atmosphere-ocean condition, and the predictions of climate dynamical/statistical models, the present El Niño event should be further to decay in the following boreal spring and be likely to end in May 2016. Subsequently, an ENSO-neutral phase is expected to maintain in the following summer.

We will closely monitor the development of ENSO conditions and update the ENSO wrap-up in time.