图1 大气层对成像的影响示意图
图2 Dark Subtraction Parameters面板(Band Minimum)
反射率= 增益 * DN值+ 偏移
表1回归解算的a和b值
波段 | 增益(a) | 偏移(b) |
Band1 | 1.02 | -34 |
Band2 | 1.22 | -18 |
Band3 | 0.92 | -9 |
Band4 | 1.21 | -16 |
Band5 | 0.99 | 4 |
Band7 | 0.94 | 3 |
第三步、线性变换
图3Thermal Atm Correction Parameters面板
图4 快速大气校正流程图
图5 QUick Atmospheric Correction Parameters面板
图6基本参数设置
Model Atmosphere | Water Vapor (std atm-cm) | Water Vapor (g/cm2) | Surface Air Temperature |
Sub-Arctic Winter (SAW) | 518 | 0.42 | -16 °C or 3 °F |
Mid-Latitude Winter (MLW) | 1060 | 0.85 | -1 °C or 30 °F |
U.S. Standard (US) | 1762 | 1.42 | 15 °C or 59 ° |
Sub-Arctic Summer (SAS) | 2589 | 2.08 | 14 °C or 57 ° |
Mid-Latitude Summer (MLS) | 3636 | 2.92 | 21 °C or 70 ° |
Tropical (T) | 5119 | 4.11 | 27 °C or 80 ° |
表2六种标准的大气模型
Latitude (°N) | Jan. | March | May | July | Sept. | Nov. |
80 | SAW | SAW | SAW | MLW | MLW | SAW |
70 | SAW | SAW | MLW | MLW | MLW | SAW |
60 | MLW | MLW | MLW | SAS | SAS | MLW |
50 | MLW | MLW | SAS | SAS | SAS | SAS |
40 | SAS | SAS | SAS | MLS | MLS | SAS |
30 | MLS | MLS | MLS | T | T | MLS |
20 | T | T | T | T | T | T |
10 | T | T | T | T | T | T |
0 | T | T | T | T | T | T |
-10 | T | T | T | T | T | T |
-20 | T | T | T | MLS | MLS | T |
-30 | MLS | MLS | MLS | MLS | MLS | MLS |
-40 | SAS | SAS | SAS | SAS | SAS | SAS |
-50 | SAS | SAS | SAS | MLW | MLW | SAS |
-60 | MLW | MLW | MLW | MLW | MLW | MLW |
-70 | MLW | MLW | MLW | MLW | MLW | MLW |
-80 | MLW |
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