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i Detection of Smoke and Dust Aerosols Using Multi-sensor Satellite ...

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these b<strong>and</strong>s, including reflective solar b<strong>and</strong>s 1-11 (excluding Aqua b<strong>and</strong> 6 due to a<br />

number <strong>of</strong> inoperable detectors) <strong>and</strong> 17-19 <strong>and</strong> thermal emissive b<strong>and</strong>s 20, 22, 23, 29, 31,<br />

<strong>and</strong> 32 are listed in Table 7.1.<br />

All the values represent the BBR shifts relative to b<strong>and</strong> 1 in two directions. The<br />

positive spatial shift means that certain b<strong>and</strong> observes the same Earth target earlier than<br />

b<strong>and</strong> 1, while the negative sign indicates the reverse case. In the table, b<strong>and</strong>s located in<br />

the same NIR FPA as b<strong>and</strong> 1 have small spatial shifts. The spatial shift <strong>of</strong> the VIS FPA is<br />

also small except for b<strong>and</strong>s 8-11 whose shifts are up to108 m in scan direction for Terra<br />

MODIS. For the cold FPA, the maximum spatial shift <strong>of</strong> Terra MODIS is 85 m<br />

along-scan <strong>and</strong> 122 m along-track while it is 277 m along-scan <strong>and</strong> 270 m along-track for<br />

Aqua MODIS. The st<strong>and</strong>ard deviation varies significantly with the spatial resolution <strong>of</strong><br />

each b<strong>and</strong>. The higher resolution b<strong>and</strong>s have smaller st<strong>and</strong>ard deviation, consequently,<br />

higher accuracy <strong>of</strong> results. The results in Table 7.1 clearly show that the BBR shifts are<br />

much larger in Aqua MODIS for any b<strong>and</strong> pair with one on the cold FPA <strong>and</strong> the other on<br />

the warm FPA. For example, the BBR shift between Aqua b<strong>and</strong> 5 <strong>and</strong> b<strong>and</strong> 4 in track<br />

direction is estimated to be 333m.<br />

Table 7.1: The average spatial deviation for Terra <strong>and</strong> Aqua MODIS during <strong>sensor</strong><br />

operation year (year 2000-2007 for Terra MODIS <strong>and</strong> year 2002-2007 for Aqua MODIS).<br />

All values are given in meters.<br />

B<strong>and</strong> Terra Aqua<br />

Track std 1<br />

Scan std Track std Scan std<br />

2 6 8 -2 5 -5 5 3 4<br />

106

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