EPA-91-U1L1-02-108

091

1,360 千元

2002/02/22

2002/12/31

陳正平

監資處

國立台灣大學大氣科學系

環境資訊系統

沙塵暴、大氣沙塵模式、TAQM

Dust storm,atmospheric dust model,Taiwan Air Quality Model

蔡富容、王自發

每年春季中國西北地區容易發生大範圍沙暴現象，部分沙塵可經大氣傳送到達台灣地區，可能造成本地居民呼吸系統與眼睛的不適，導致能見度降低，甚至影響飛航安全，改變太陽輻射量與降水機制。統計資料顯示，大陸地沙塵暴的發生頻率在近幾十年內有逐漸增加的趨勢，因此對沙塵暴影響的分析與預報有其必要與迫切性。由於沙塵暴的形成與傳送主要受源區地表特性與區域氣象條件的控制，因此欲準確地預報沙塵暴，必須能對起沙機制與綜觀氣象場有詳細模擬的能力。此研究對可能侵台之大陸沙塵進行綜觀氣象分析，並發展適用於台灣地區之數值模式進行沙塵暴模擬，以建立預警制度，及早告知民眾事前防範；同時並提供本署啟動襲台沙塵密集觀測採樣與健康效應評估急診監測網之參考。本計畫完成項目包括：（1）發展適用於東亞與台灣地區的大氣沙塵預報系統，包括TAQM與NAQPM兩沙塵模式；（2）分析影響台灣地區的大陸沙塵綜觀天氣型態與相關觀測資料；（3）根據氣象分析與數值預報結果，協助評估大陸沙塵個案侵台之時間、影響範圍及濃度，以協助預警指揮中心進行沙塵暴守視與預警作業；（4）建立大陸沙塵預報網頁，將模擬動畫與相關分析資料以月曆型態建立資料儲存庫。2002年春季共有7波顯著襲台沙塵事件，另有兩波不顯著事件。本計畫的沙塵模式預報結除了一次虛報一次漏報外，其餘均能大致掌握其侵台時間與範圍，而在最高濃度預報的表現上相對較差。虛報事件是由於華南雲雨將沙塵洗除，而模式未考慮洗除機制所致，目前已加入此機制。漏報事件是由於修改模式時誤植起沙量，以致雖模擬到沙塵來臨，但濃度量級不正確，因而列為漏報；目前也已修正錯誤。整體評估國內外各個大氣沙塵模式對侵台沙塵事件的預報結果，本計畫的TAQM模式表現最優。

沙塵暴、大氣沙塵模式、TAQM

0000018178.zip

102MB

[期末報告]公開完整版

2014/10/31 下午 02:07:46

Large-scale dust storms originated at the Northeastern Chine frequently occur during springtime. Some of the elevated dust particle may be transported long distance through atmospheric circulation to the Taiwan area. The possibly effects of these atmospheric dust particles include the influence on public health, lowering the visibility and even causing aviation safety concerns, reducing solar radiation to the surface, and altering the precipitation processes. Due to its increasing frequency of occurrence during the past decade, it is essential to study the mechanisms controlling the transport of yellow dust to Taiwan, and develop forecasting capability for early warning. The elevation and transport of atmospheric dust particles is controlled by the surface conditions of the source region (deserts) and the regional weather patterns. The goal of this study is to develop an modeling system that can accurately simulation the elevation of dusts as well as their subsequent transport in the regional scales, and to help establishing an early-warning system for the Environmental Protection Agency for alerting the public regarding to their health, and to provide lead time of operation for the dust-sampling group and health effect evaluation group. The accomplishments of this project include: (1) development of dust storm forecasting models suitable for use in the East Asia region and Taiwan area, this include a TAQM/dust model and NAQPM/dust model; (2) daily watch of the dust storm events by analysis of the synoptic weather patterns and observation data relevant to Asia dust storms; (3) evaluation of the time, duration, area extent and concentration of possible events of dust reaching Taiwan, so as to assist the issue of warnings by the operation center of EPA; (4) built a web site of atmospheric dust forecasting, using calendar-style data bank in exhibiting the movies of dust storm simulation and analysis data. Among the 7 significant and 2 minor dust events occurred during the Spring of 2002, our forecasting model missed one of the event and false-alarmed the other. The false-alarm case was an event with strong rain scavenging effect, which was not considered in the TAQM/dust model at the time. Improvement has been made to include this rainout mechanism. For the event that was missed by the model, an error in coding was made when modifying the model, such that the event was actually captured but the order of dust concentration was wrong and is thus counted as a missed case. Corrections have been made soon after. For the rest of the events, the forecasting model did fairly well on the arrival time, duration, and area extent, but not as satisfactory in the maximum mass concentrations. An overall evaluation of the performance of our and foreign models was made, and we found that the TAQM/dust model is superior to all other models in forecasting dust events in Taiwan.

Dust storm,atmospheric dust model,Taiwan Air Quality Model