Investigating impacts of dust events on atmospheric surface temperature in Southwest Asia using AERONET data, satellite recordings, and atmospheric models

TL;DR

This study addresses how dust outbreaks in Southwest and Central Asia affect atmospheric surface temperature and how the response correlates with dust-strength measures. It combines long-term AERONET AOD measurements at 870 nm ($\tau$) and Angstrom Exponent ($\alpha$) with midday temperature, MODIS AOD at 550 nm, and HYSPLIT backward trajectories to locate dust sources and quantify delayed temperature responses via the metric $r_m(\tau, T)$ across delays. The results show that dust outbreaks mostly cool the surface, with delays up to about 2 days and temperature changes typically below 5 °C, though some events warm the surface; near-source sites show synchronous $\tau$ and $T$ variations, while distant sites exhibit larger delays. The study demonstrates a robust, multi-dataset approach for regional dust–temperature coupling and source attribution, offering insights for climate modeling and dust transport research.

Abstract

Dust layers have already been reported to have negative impacts on the radiation budget of the atmosphere. But the questions are: How does the atmospheric surface temperature change during a dust outbreak, and what is its temporal correlation with variations of the dust outbreak strength? We investigated these at selected AERONET sites, including Bahrain, IASBS, Karachi, KAUST Campus, Kuwait University, Lahore, Mezaira, Solar Village, in Southwest Asia, and Dushanbe in Central Asia, using available data from 1998 to 2024. The aerosol optical depth at 870 nm and the temperature recorded at each site are taken as measures of dust outbreak strength and atmospheric surface temperature, respectively. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and the aerosol optical depths recorded by the Moderate Resolution Imaging Spectroradiometers (MODIS) on board the Aqua and Terra satellites are used to specify the sources of the dust outbreaks. Our investigations show that in most cases, the temperature decreases during a dust outbreak, but in a considerable number of cases, the temperature rises. Temperature changes are mostly less than 5 °C. We found that a dust outbreak may affect the temperature even up to two days after its highest intensity time. This effect is more profound at sites far from large dust sources, such as IASBS in northwest Iran. For sites that are located on either a dust source or very close to it, the temperature and dust optical depth vary almost synchronously.

Figures (6)

• Figure 1: Topography map of the investigation region, locations of the nine selected AERONET sites (white balloons), and main dust sources (yellow ovals)
• Figure 2: Five-year average precipitation ($2019-2023$) in the region obtained from the NASA GPM IMERG final run daily product GPM_IMERG_V07
• Figure 3: Five-year average surface air temperature ($2019-2023$) in the region obtained from the NASA FLDAS Noah L4 monthly FLDAS_NOAH_CHIRPS_v001
• Figure 4: (a)-(i) Monthly variation of $\tau$, $\alpha$, and temperature at nine AERONET sites: Bahrain, Dushanbe, IASBS, Karachi, KAUST Campus, Kuwait University, Lahore, Mezaira, and Solar Village.
• Figure 5: (a) Time series of $\tau$ at 870 nm, temperature (${^\circ} \mathrm{C}$), and correlation coefficient from $19-30$ June 2010; (b) 48 h HYSPLIT backward trajectories ending at 300 m, 500 m, and 700 m AGL at 12:00 UTC on 24 June 2010, overlaid on the MODIS AOD at 550 nm on 23 June 2010, IASBS site.