Backward rajectory Analysis using NOAA HYSPLIT Model.doc

Backward Trajectory Analysis using NOAA HYSPLIT Model
Leung Siu Ki, Francis
Summer Internship at the Hong Kong Observatory 2006
Supervisor: Leung, . Wu
July 2006
Table of Contents
Introduction 1
HYSPLIT Model
Overview 1
putational Method 2
Error Sources in Trajectory Calculation 3
Incorporating 20km-ORSM data into HYSPLIT Model 3
Comparison of ORSM Data and Global Model Data 5
Backward Trajectory Analysis
Single Episode 6
Seasonal Analysis 8
Conclusion 10
Future Work 10
References 11
Introduction
A deteriorating trend is observed in the visibility in Hong Kong for the last two decades and the problem seems to be worsening in the recent years. After having a record breaking high percentage of time with reduced visibility observed at the Hong Kong Observatory in 2004, the reduced visibility observed at the Hong Kong International Airport continues to climb and hit the highest record since the start of its operation. Since the degrading visibility is affecting the health of local people as well as the economy, it is necessary to identify the sources contributing to visibility impairment. Several tools have been developed and are available to aid the studies of low visibility, and a category of them is known as the atmosphere transport and dispersion models, which are also called the air quality models. By simulating the movements of visibility impairing pollutants such as sulfur particle in the atmosphere, the source of emission can be identified. Back trajectory analysis is a technique to identify the source based on the simulation results obtained from these models.
HYSPLIT Model
Overview
HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model is one of the atmospheric transport and dispersion models most frequently used in large-scale research. It was developed by the Air Resources Laboratory (ARL) of the National Oceanic and Atmospheric Administration (NOAA) and it has been upgraded in April 2001 as a joint effort betwe