Scaling properties of aerosol optical thickness fields retrieved from MFRSR local network data and MODIS satellite measurements
Abstract
The statistical scale-by-scale analysis, for the first time, has been applied to the aerosol optical thickness (AOT) retrieved from the Multi-Filter Rotating Shadowband Radiometer (MFRSR) networks and Moderate Resolution Imaging Spectroradiometer (MODIS). The MFRSR data were collected in September 2000 from the dense local network and have 20 sec time resolution while the MODIS data are the Level 2 Aerosol product at 10 km resolution. We found that temporal and spatial variability of AOT can be roughly separated into three scale-invariant regimes: (1) microscale (0.5--15 km) where fluctuations are governed by 3D turbulence; (2) transition towards large-scale 2D turbulence (15--100 km) and (3) mesoscale variability (scales up to 100--600 km) with increasing influence of AOT boundedness. For synoptic scales (after 600--1000 km), AOT fields become stationary and loose correlation. Analyzing scaling properties of AOT time series we discovered a good correlation between AOT spectral exponents (at both local and transition scales) and the aerosol scaling heights as well as between spectral exponents and concavity/convexity of the site topography. Turbulence-based explanations have been suggested. Finally, a consistency in scaling properties between MODIS and MFRSR retrieved AOT at scales from 10 km to 200-300 km has been reported.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....3053A