Hi Nitish,

It depends of what variable you are interested in analyzing for temporal trends and if you are just interested in the spatial and temporal trends or if you are also interested in quantifying the actual concentration of the pollutant. Let’s say for instance, a common parameter monitored in coastal water quality is turbidity or the related concentration of suspended sediments. If you want to quantify the actual numbers you need in situ data to analyze for correlations with remote sensing data but if you are just interested in the trends (if it is increasing or decreasing) you may just relay on associations reported in literature and if those are good then just analyze for the trends of the remote sensing data. It will give you an idea if the temporal trends go up or down or if there are spatial patterns of turbidity like for instance the plumes from mouths of rivers.  The MODIS/Terra Surface Reflectance Daily L2G Global 250m SIN Grid V005 (MOD09GQ) is a relatively friendly product to use that can be used to estimate turbidity in coastal waters. It  records surface reflectance data is provided in two channels, but for turbidity is commonly used the visible range between 620 and 670 nm (Band 1).  It can be downloaded from the EOS Clearing House (ECHO) website of NASA’s Earth Observing System Data and Information System (EOSDIS, 2013) http://reverb.echo.nasa.gov/reverb/#utf8=%E2%9C%93&spatial_map=satellite&spatial_type=rectangle

For spatial trends you can just look at the trends in water surface reflectance and for temporal trends you can pick random representative sites (or even fixed sites if you have good reasons to support it) using GoogleEarth™and record the coordinates of the sites also using GoogleEarth™. You can import those coordinates into ArcMap and use the “extract values to point” function of ArcMap 10.2 to extract the water surface reflectance at each of the sites, from the selected images that are could free. You can also use the MOD09Q1 product which is a compilation of the good pixels during 8 days. That reduces the burden of having to search for free clouds images. You can get continuous data since 2000 or since 2003 if you use the equivalents from these products from the Satellite Aqua.   For each site you can get the statistics that you need (mean media etc.) at the intervals of time you want (weekly, monthly, annually, etc.)  and plot your data in a time series curve and you can visualize your temporal trends. You can use statistical software like SAS to check for significance in the trend and you can adjust a model to that trend that would allow you to estimate a forecast.  These are some studies that have used that product:

http://dx.doi.org/10.3390/rs2122713

http://dx.doi.org/10.1016/j.ecss.2008.11.013

 If you are interested in other parameters you could also follow similar procedure. This is other paper that looks at coastal water quality trends but at different water quality parameters:

  http://dx.doi.org/10.1016/S0025-326X(01)00040-6 

 Hope this helps,

Max

Hi Nitish,

Send your request to Tim Malthus at CSIRO. He is expert in that area. Hope this helps.

Cheers.

@Dasapta Erwin Irawan and @Max Jacobo Moreno Madriñán : thank you for replies and it helps me to understand from where i can start. thank you once again.

@ Abdulwasey Mohammed: As per your suggestion, i have sent my request. Thank you.