From the satellite operator:
Important Reminder about SWIR Observation
Thank you for continuing to use and support our GPR service. Please carefully read the following important notice from GPR Office.
In connection with increasing temperature of the SWIR detector, there have been some cases in which acquired SWIR data turn out to be saturated. So far, newly acquired data through GPR service has been provided only after we confirm that it has no particular problem with regard to such saturation. However, while examining some scenes acquired in November 2007, we recognized saturation of DN values in Band5 to Band9 for the data from high-reflectance areas like deserts. In response to this, we are going to take the best possible countermeasures such as setting a lower observation gain for SWIR. Nevertheless, deterioration of the data will be inevitable because ASTER is now working beyond its designed lifetime.
Therefore, even if there is saturation in SWIR data from future GPR observations, we will require users to purchase such data as long as it satisfies certain conditions (cloud cover percentage etc.). Please kindly understand this situation before you submit a GPR request.
Such saturation has been most obvious for SWIR Band5 to Band9, but not for Band4 yet, which still has some range margin. Also, please be advised that this issue is unique to SWIR and poses no problem on VNIR and TIR.
From now on, if SWIR data is essential for your purpose, please let GPR Office know in advance at the time of submitting a GPR request. We will inform you about a prediction of SWIR data saturation, considering the detector's temperature at that point and your target area.