###### Abstract  
Research concerning the response characteristics of lower atmosphere to volcanic eruption is a key and hot topic in the field of volcanic environment research. Against the background of a submarine volcano in the South Pacific island country of Hunga Tonga Tonga-Hunga Ha'apai (HTHH) on 15 January 2022, this paper explores the response characteristics of this volcanic eruption on environmental factors in the lower atmosphere region using a priori data such as ERA5 reanalysis data, water vapor data from GNSS inversion and surface temperature data from Landsat inversion for the Tonga Islands region. Among them, (1) The amount of precipitable water (PWV) in Tonga was abnormally high on 15 January. (2) The water vapor flux was mainly in the lower space below 850 hPa. (3) The average surface temperature in December 2021 was higher. In February 2022, the average surface temperature was lower. (4) There was a low-pressure center near 30\({}^{\circ}\) S on the south side of Tonga volcano on 14 January, and a new low-pressure center was formed on the east side of Tonga volcano after the eruption of Tonga volcano on 15 January. Furthermore, the precipitation area of Tonga increased in January and decreased in February 2022. The PWV values, water vapor fluxes, temperature and circulation response characteristics, and precipitation characteristics show that the volcanic eruption affected part of the atmospheric and oceanic circulation, and water vapor was transported to the low-pressure center along the direction of atmospheric circulation. With the continuous water vapor transport, precipitation formed in Tonga, and the intensity and area of precipitation in Tonga increased significantly in January. Thus, the volcanic eruption could have significantly triggered the response between the low-pressure center, PWV, precipitation and surface temperature in the lower atmosphere, which influenced the environmental characteristics of this eruption. T 20  
are most powerful when combined with other methods, such as low-pressure centers, water vapor, precipitation, surface temperature, and volcanological studies [3; 4]. Significant volcanic eruptions regulate atmospheric and oceanic circulation in the lower atmosphere and thus determine the genesis and activity of cyclones in the Pacific [5]. Meanwhile, cyclone and Sea Surface temperature (SST) [6], large-scale circulation [7; 8] and precipitation [9] were directly related. Cyclones will affect the direction of circulation and thus affect water vapor transport, which is a necessary condition for forming precipitation [10]. Tonga is located in the Southwest Pacific Convergence Zone (SPCZ), which is generally regarded as a breeding area for cyclones [11] because the region within 10 degrees of the polar position of the average SPCZ has favorable conditions for the occurrence of tropical cyclones [12; 13]. Volcanoes release large amounts of volcanic gases in the lower atmosphere when they erupt, with water vapor accounting for 60% to 90% of the total gas volume [14]. During its change, water vapor absorbs and releases large amounts of latent heat, directly affecting ground and air temperatures and thus influencing the formation and evolution of weather systems. Numerous studies have shown anomalous changes in water vapor both before and after geological hazards [15; 16; 17]; for example, there may be a sudden increase in columnar water vapor in the atmosphere before an earthquake, and this is attributed to increased evaporation due to increased surface heat flux. Water vapor may decrease after an earthquake, while over the ocean, water vapor is found to increase after an earthquake [18]. Severe weather conditions related to significant transient changes in atmospheric water content, such as low pressure and storms, can be well identified by the abrupt change in precipitable water vapor (PWV) [19; 20].