
南太平洋典型岛国海洋生态环境状况及其对汤加火山爆发的响应
龚芳, 朱伯仲, 李腾, 王雨馨, 李鸿喆, 何贤强, 张清
海洋学研究 ›› 2023, Vol. 41 ›› Issue (3) : 101-114.
南太平洋典型岛国海洋生态环境状况及其对汤加火山爆发的响应
Remote sensing research on temporal and spatial variations of ecological environments and response for Tonga volcanic eruptions in South Pacific island countries
南太平洋岛国大多四面环海且国土面积狭小,多为生态环境脆弱区。基于此,本文利用多源卫星数据,对瑙鲁、帕劳、图瓦卢、马绍尔群岛四国的海洋生态环境进行监测,基于长时间序列遥感结果的回溯,分析了其时空变化,并对比分析了汤加火山爆发前后,各国生态环境是否发生显著变化。结果显示:1)在气候态时空分布上,南太平洋岛屿国家周边海域海表温度和透明度一直维持在较高水平,叶绿素和净初级生产力则随离岸距离增加快速下降;2)升温、酸化和海平面升高是四个岛屿国家周边海域面临的共同问题;3)汤加火山的爆发对于南太平洋四岛国的沿岸悬浮物质量浓度、海表温度等无明显影响;4)火山爆发前半个月海岛地表温度以及周边海域悬浮物质量浓度异常升高的现象对利用遥感手段进行灾害预警预报具有启示作用。
The unique geographical features of the island countries in South Pacific, which are surrounded by sea and small in size, make most of the island countries in this region "ecologically fragile areas". Based on this, multi-source satellite data were used to monitor the marine ecological environment of Nauru, Palau, Tuvalu, and the Marshall Islands. It was also focused on whether there have been significant changes in the ecological environment of various countries before and after the Tonga volcanic eruption, to help to understand the impact of the Tonga volcanic eruption. The results show that: (1) In terms of temporal and spatial distribution of climatic states, the sea surface temperature and transparency of the surrounding waters of the South Pacific island countries maintain a relatively high level, while chlorophyll and net primary productivity decrease rapidly with the increase of offshore distance. (2) Warming, acidification and sea level rising are common problems faced by the sea areas of the four island countries. (3) The eruption of the Tonga Volcano has no significant impact on the coastal TSM mass concentration and SST. (4) The phenomenon of abnormally rising surface temperature and changed suspended matter mass concentration of the island in the first half month of the volcanic eruption has implications for disaster warning and forecasting using remote sensing methods.
海洋生态环境 / 南太平洋岛国 / 汤加火山爆发 / 遥感 / Sentinel-2 / Landsat-8
marine ecological environment / South Pacific island countries / Tonga volcanic eruption / remote sensing / Sentinel-2 / Landsat-8
[1] |
|
[2] |
|
[3] |
|
[4] |
|
[5] |
|
[6] |
|
[7] |
|
[8] |
外交部. 大洋洲[EB/OL]. (2023-07-05) [2023-08-21]. https://www.fmprc.gov.cn/web/gjhdq_676201/gj_676203/dyz_681240/
Ministry of Foreign Affairs. Oceania Countries[EB/OL]. (2023-07-05) [2023-08-21]. https://www.fmprc.gov.cn/web/gjhdq_676201/gj_676203/dyz_681240/
|
[9] |
. This paper describes a blended sea-surface temperature (SST) data set that is part of the National Oceanic and Atmospheric Administration (NOAA) Climate Data Record (CDR) program product suite. Using optimum interpolation (OI), in situ and satellite observations are combined on a daily and 0.25° spatial grid to form an SST analysis, i.e., a spatially complete field. A large-scale bias adjustment of the input infrared SSTs is made using buoy and ship observations as a reference. This is particularly important for the time periods when volcanic aerosols from the El Chichón and Mt. Pinatubo eruptions are widespread globally. The main source of SSTs is the Advanced Very High Resolution Radiometer (AVHRR), available from late 1981 to the present, which is also the temporal span of this CDR. The input and processing choices made to ensure a consistent data set that meets the CDR requirements are summarized. A brief history and an explanation of the forward production schedule for the preliminary and science-quality final product are also provided. The data set is produced and archived at the newly formed National Centers for Environmental Information (NCEI) in Network Common Data Form (netCDF) at doi:10.7289/V5SQ8XB5.\n
|
[10] |
|
[11] |
|
[12] |
|
[13] |
|
[14] |
|
[15] |
|
[16] |
|
[17] |
Seawater pH is a direct proxy of ocean acidification, and monitoring the global pH distribution and long-term series changes is critical to understanding the changes and responses of the marine ecology and environment under climate change. Owing to the lack of sufficient global-scale pH data and the complex relationship between seawater pH and related environmental variables, generating time-series products of satellite-derived global sea surface pH poses a great challenge. In this study, we solved the problem of the lack of sufficient data for pH algorithm development by using the massive underway sea surface carbon dioxide partial pressure (pCO2) dataset to structure a large data volume of near in situ pH based on carbonate calculation between underway pCO2 and calculated total alkalinity from sea surface salinity and relevant parameters. The remote sensing inversion model of pH was then constructed through this massive pH training dataset and machine learning methods. After several tests of machine learning methods and groups of input parameters, we chose the random forest model with longitude, latitude, sea surface temperature (SST), chlorophyll a (Chla), and Mixed layer depth (MLD) as model inputs with the best performance of correlation coefficient (R2 = 0.96) and root mean squared error (RMSE = 0.008) in the training set and R2 = 0.83 (RMSE = 0.017) in the testing set. The sensitivity analysis of the error variation induced by the uncertainty of SST and Chla (SST ≤ ±0.5 °C and Chla ≤ ±20%; RMSESST ≤ 0.011 and RMSEChla ≤ 0.009) indicated that our sea surface pH model had good robustness. Monthly average global sea surface pH products from 2004 to 2019 with a spatial resolution of 0.25° × 0.25° were produced based on the satellite-derived SST and Chla products and modeled MLD dataset. The pH model and products were validated using another independent station-measured pH dataset from the Global Ocean Data Analysis Project (GLODAP), showing good performance. With the time-series pH products, refined interannual variability and seasonal variability were presented, and trends of pH decline were found globally. Our study provides a new method of directly using remote sensing to invert pH instead of indirect calculation based on the construction of massive underway calculated pH data, which would be made useful by comparing it with satellite-derived pCO2 products to understand the carbonate system change and the ocean ecological environments responding to the global change.
|
[18] |
|
[19] |
|
/
〈 |
|
〉 |