where R(2.3) = AVIRIS Reflectance at 2.3 um 
R(2.1) = AVIRIS Reflectance at 2.1 um 
  
  
  
  
A, Flight F 
5 
  
  
  
^ JE 
  
  
Figure 1. ASPECT Methane detection results, using a 
Normalized Differential Methane Index to identify 
regions of high methane content, these points 
correlated to known seep locations off of Santa 
Barbara, CA. 
The illustration in Figure 1 demonstrates two sequential parallel 
AVIRIS flight paths (~5 minutes apart): (1) from the Holly 
Seep with a trajectory across the Goleta Seep, followed by (2) a 
path downwind of the first path across the Coal Oil Point Seep. 
In this image the correlation between the methane seeps and the 
locations of highest NDMI is apparent, with the highest 
methane amounts (7250 ppm) being over the known seep 
regions. 
Despite the low sunglint in the data, the research demonstrated 
that the technique is viable, and researchers hypothesized that 
more accurate results could be obtained under proper conditions 
with a more advanced instrument. From these positive results 
the LM team researched the use of the TIMS sensor for 
measuring methane over sunglint. 
2.2 TIMS flown on Airship 
In September 2010, LM deployed the TIMS sensor to collect 
data over sunglint water of the southern tip of the San Francisco 
Bay as well as over-ground data for in-situ measurements in 
Mountainview Park, CA. The day turned out to be a success 
with over 500 sample spectra collected over sunglint, and 
hundreds of readings taken over both Moffet Field and a park 
(built over a landfill). It was a perfect day for collecting sunglint 
data as well, with sunny cloud free skies and little wind. 
Figure 2 shows the route the airship took over the San 
Francisco bay area. The airship started over the Moffet Field 
hangar (1), Flew over Moffet field (2). From Moffet, the airship 
continued over the Mountainview park landfill where LM took 
in situ methane measurements (4). After hovering over the park 
for in situ measurements, the airship headed for gathering 
sunglint data over the water. The airship made one loop over the 
water to take numerous samples (7-8). Before heading back 
   
   
over the landfill, the airship paused for a second collection for 
ground-based in situ measurements (9), and then back to 
Moffett Field 
d 
  
Figure 2. The Route of the Airship with TIMS 
to land (12). Hundreds of data samples were taken during this 
experiment. 
2.3 TIMS Sensor 
The LM TIMS sensor uses low noise 2D arrays fed by a grating 
mapping spectrometer. TIMS uses a Littrow spectrometer 
design, which provides a compact package for achieving high 
spectral resolution with no moving parts. 
A camera was operating and aimed from the airship over the 
region of measurement (Figure 3). The line in the image 
represents the TIMS sensor-imaging slit for collecting reflection 
data from the water below on the camera frame. 
   
video frame containing siit approximately as 
Shown of water-no-glint, for spectral image AV302 
Figure 3. Camera image from the Airship over region of no 
sunglint. Linear line is the TIMS sensors imaging 
slit. 
In Figure 3 the TIMS mirror is not rotated forward and the view 
is directly to nadir, out of the sunglint area. There is no light 
reflected up to the airship from the water in this case. 
     
   
    
    
    
     
  
  
  
    
    
    
   
  
   
   
    
  
  
   
   
    
    
   
     
  
  
Figure 4 
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