Quality (philosophy)

Air pollution

Quantum mechanics

Ecology

Biology

Weather Research and Forecasting Model

Boundary (topology)

Pollution

Troposphere

Computer science

Initialization

Chemical transport model

Geology

Physics

Organic chemistry

Particulates

Mathematics

Environmental science

Mathematical analysis

MOZART

Air quality index

Chemistry

Programming language

Meteorology

Atmosphere (unit)

Atmospheric sciences

Ozone

Advances in Space Research

Accurate representation of initial and boundary conditions of chemical species in numerical models is a major challenge for air quality prediction. Model for Ozone and Related chemical Tracers, version 4 (MOZART-4) is an offline global chemical transport model simulating various gases and particulates in the atmosphere. In this work, MOZART-4 analysis is used to modify the chemical boundary conditions over India to improve the forecast in an online-coupled model. A sensitivity study has been performed using the Weather Research and Forecasting (WRF) model coupled with Chemistry model (WRF-Chem) for the highly polluted winter month of December 2016. Daily two parallel experiments are performed from the WRF-Chem model with and without updating chemical initial and lateral boundary conditions using MOZART-4 analyses. Results show that the tropospheric ozone (O3) and surface carbon monoxide (CO) forecasts are improved by 6% and 20%, respectively when MOZART-4 analysis is used to update chemical initial and lateral boundary conditions. Moreover, prediction of O3 and CO is also improved vertically (reduction in root mean square difference by 58% and 26%, respectively) in different forecast lengths. The percentage improvement in surface CO, particulate matter of size less than 2.5 μm (PM2.5) and particulate matter of size less than 10 μm (PM10) forecasts is ∼22%, ∼4.3% and ∼20%, respectively when compared against ground observations from Central Pollution Control Board (CPCB), New Delhi stations. Overall, we observed improvement in O3, CO, PM2.5 and PM10 forecast using WRF-Chem model after initialization of chemical conditions from MOZART-4 analysis.

Impact of chemical initial and lateral boundary conditions on air quality prediction