Geographical climate of Xuwen Coral Reef Nature Reserve

Jiaowei Township and xilian town, which are adjacent to the reserve, are coastal areas, surrounded by the sea on three sides, with low terrain, high in the north and low in the south, and mostly sandy soil and sandy soil. The coastal and intertidal zones of the reserve are basically beaches and shore reefs, which are mainly composed of sandy argillaceous clastic rocks in coastal-shallow sea facies and gypsum-bearing clastic rocks in lake facies. The lithology is mainly light gray-green siltstone, brown-red mudstone and gray-black basalt. There are many corals growing on the gray-black basalt, and they are also lush.

2. Climate

The reserve belongs to the tropical monsoon climate zone, with abundant sunshine and high annual average temperature, and the four seasons are not obvious; Abundant rainfall and large annual change rate; Rain and heat are in the same season, and dry and wet seasons are more distinct.

3. Tides and tidal currents

Tide: the tidal phenomenon in Xuwen coastal zone is mainly formed after the Pacific tidal wave enters the South China Sea. Qiongzhou Strait between xuwen county and Hainan Island, facing north and south, runs east and west, just like a strip inland waterway. The east exit and the west exit are connected with qi zhou Ocean and Beibu Gulf respectively. Coupled with the influence of the perennial monsoon in the southeast, southwest and northeast and the uneven topography at the bottom of the trough, an irregular mixed tide is formed. The reserve is mainly controlled by the irregular diurnal tide in Beibu Gulf.

Tidal current: Tidal current in the reserve is unevenly distributed. The sea area connected with Qiongzhou Strait at the southern end and the sea area west of Shuiwai Angle have high velocity, while the sea area west of Dongchang in the bay has little or no obvious velocity.

4. Sea surface circulation

The surface circulation of the reserve is mainly controlled by the surface circulation of Beibu Gulf, and strongly influenced by the surface circulation of Qiongzhou Strait in winter, and the circulation direction is mainly north and northwest. In summer, it is strongly influenced by the southwest monsoon and the eastward circulation of Qiongzhou Strait, and the circulation direction is mainly from southeast to south.

5, water temperature distribution and seasonal changes

The annual minimum water temperature in the protected area is about 65438 0℃. The highest water temperature appears in July, about 30.5℃, and the annual average water temperature is about 26℃.

6. Bad weather

Mainly affected by tropical cyclones, typhoons, hail, tornadoes and cold waves.