Publications

Yao, Q; Li, ZQ; Fan, C; Xu, H; Wang, SH; Chen, ZT (2024). Study on Global Spatial Distribution of Surface-Atmosphere Clutter in Mid-Infrared Atmospheric Strong Absorption Band. SPECTROSCOPY AND SPECTRAL ANALYSIS, 44(12), 3504-3512.

Abstract
The mid-infrared (MIR) atmospheric strong absorption wavelength bands (near 2.7 and 4.3 mu m) have the characteristics of suppressing background clutter signals, which are often used on the payload of infrared early warning satellites to achieve stable detection and tracking of targets. The background clutter fluctuation level has an important impact target detection, and it is of great significance to study the spatial domain fluctuation of surface atmosphere clutter near the 2.7 and 4.3 mu m bands. First, the MODTRAN radiative transfer model is used to iteratively simulate the optical depth (OD) of water vapor and CO2, under six standard atmospheric models. screen the strong absorption bands according to the criterion of OD1>1, and intersect the band calculation results under various atmospheric models. The final strong absorption bands were 2.52 similar to 2.83 and 4.18 similar to 4.47 mu m. Then, global monthly averaged surface and atmosphere background products are produced based on remote sensing satellite data products and data assimilation information. Among them combined with the monthly average surface reflectance/emissivity products (MYD09A1/ MODIIC3) of MODIS shortwave infrared and mid-infrared bands (2.13, 3.75, 3.96 and 4.05 mu m), the non negative matrix factorization (NMF) method was used to reconstruct global surface reflectance/emissivity products at strongly absorbing bands: Produce monthly averaged global surface temperature products based on ERAS reanalysis datas The global monthly average products of water vapor and cloud optical thickness (COT) are obtained by splicing and fusing MODIS atmospheric products (MODOS L2 and MOD06 L2) respectively: The CO2 global monthly average product comes from the data assimilation product of the OCO2 satellites In order to spatially match various data products and save computing resources, global products are limited to the 60 degrees north and south latitude range and resampled to a spatial resolution of 1 degrees X1 degrees; Next, under cloudy and cloud free conditions, the background clutter ingensity of two strong absorption bands was simulated and calculated pixel by pixel, and the spatial distribution pattern of clutter was analyzed, Finally, the 11x11 square window neighborhood statistics method was used to calculate the clutter spatial domain fluctuation in the simulation results. convert the clutter luctuation under 95% probability, and conduct histogram statistics. From the perspective of clutter a comparison of infrared target detection performance in two shsorption bands is given. Study results show that under eloud eunditions, the fluctuation level of background clutter in the 2.52 similar to 2.83 mu m band has the characteristics of "a point-liler prak, regional enhunerment, and overall low values". In contrast, the clutter luctuation level in the 4.18 similar to 4.47 mu m band shows the chatheteristics of "regional high values, patchy enhancement, and low values at high latitudes". Under cloud-free conditions, the background clutter flucrouton level in the 2.52 similar to 2.83 mu m band creases significantly in the low water vapor content area. In contrast, the clutter fluctuation level in the 4.18 similar to 4.47 mu m bind is generally low, and most of them are controlled within 2x10(-4) W/m(2)/se/mu m. On the global scale, the infrared target Atection performance is better in the 2.52 similar to 2.83 mu m band when there are clouds and in the 4.18 similar to 4.47 mu m band when there are no clouds. The results of this study can provide a reference basis for detecting infrared target in terms of spatial domain la and spectral band optimization, which is of great value for enhancing the detestability of targets.

DOI:
10.3964/j.issn.1000-0593(2024)12-3504-09

ISSN:
1000-0593