Publications by authors named "Mikhail D Alexandrov"
The Research Scanning Polarimeter (RSP) is an airborne along-track scanner measuring the polarized and total reflectances with high angular resolution. It allows for accurate characterization of liquid water cloud droplet sizes using the rainbow structure in the polarized reflectance. RSP's observations also provide constraints on the cumulus cloud's 2D cross section, yielding estimates of its geometric shape.
View Article and Find Full Text PDFArticle Synopsis
- The cloud droplet number concentration (N) is crucial for understanding cloud physics and aerosol-cloud interactions, but current satellite methods to retrieve N are limited and uncertain.
- A review highlights a total relative uncertainty of 78% in pixel-level retrievals for specific cloud types, which decreases to 54% for larger area averages, but accuracy against in situ observations is better than indicated by retrievals.
- Dominant errors in retrieving N stem from inaccuracies in cloud droplet effective radius (r), and improving these retrievals is essential; the review also suggests recommendations and explores new methods for better N estimates using both satellite and ground-based data.
Information content of bistatic lidar observations of aerosols from space.
Opt Express
February 2017
We present, for the first time, a quantitative retrieval error-propagation study for a bistatic high spectral resolution lidar (HSRL) system intended for detailed quasi-global monitoring of aerosol properties from space. Our results demonstrate that supplementing a conventional monostatic HSRL with an additional receiver flown in formation at a scattering angle close to 165° dramatically increases the information content of the measurements and allows for a sufficiently accurate characterization of tropospheric aerosols. We conclude that a bistatic HSRL system would far exceed the capabilities of currently flown or planned orbital instruments in monitoring global aerosol effects on the environment and on the Earth's climate.
View Article and Find Full Text PDFArticle Synopsis
- A new model for aerosol optical thickness (AOT) variability is introduced, treating AOT fields as realizations of a stochastic process rooted in a Gaussian process with a specific autocorrelation function.
- The model provides lognormal probability distribution functions (PDFs) and structure functions that behave appropriately at large scales, making it a better alternative to traditional fractal methods.
- Utilizing a year-long global MODIS AOT dataset, the study reveals two distinct regimes of AOT variability: small-scale variations linked to local marine aerosols and larger-scale trends associated with aerosols from remote continental areas, enhancing the integration of remote sensing data with climate models.
Shadow-band radiometers in general, and especially the Multi-Filter Rotating Shadow-band Radiometer (MFRSR), are widely used for atmospheric optical depth measurements. The major programs running MFRSR networks in the United States include the Department of Energy Atmospheric Radiation Measurement (ARM) Program, U.S.
View Article and Find Full Text PDF