Search found 75 matches

by OB General Science - guoqingw
Mon Jul 10, 2023 3:10 pm America/New_York
Forum: Questions/Comments
Question: Ocean Color Browser not showing Sentinel images
Replies: 7

Re: Ocean Color Browser not showing Sentinel images

Sorry about that. We have noticed the issue. The team is in developing of a new L1/2 browser. Before the issue is resolved or the new browser published, you can access the data you want through direct data access: https://oceandata.sci.gsfc.nasa.gov/directdataaccess/Level-2/
by OB General Science - guoqingw
Mon Jul 10, 2023 10:46 am America/New_York
Forum: Questions/Comments
Question: Land pixel definition in MODIS SST/ Chlorophyll level 3 data
Replies: 1

Re: Land pixel definition in MODIS SST/ Chlorophyll level 3 data

Hi, not sure what you are trying to do, but here is the tech doc for the land/water mask: https://oceancolor.gsfc.nasa.gov/resources/docs/technical/odps_land_mask.pdf

Hope it helps.
by OB General Science - guoqingw
Wed May 31, 2023 3:36 pm America/New_York
Forum: Questions/Comments
Question: Request for water leaving radiance and normalized water leaving radiance of particular region-MODIS aqua
Replies: 1

Re: Request for water leaving radiance and normalized water leaving radiance of particular region-MODIS aqua

There are many ways to get the data you need. We provide reflectance, but it's not difficult to get normalized water-leaving radiance from reflectance. You can do search and download: https://oceancolor.gsfc.nasa.gov/data/download_methods/ For monthly and/annual mean, you can also use level 3/4 brow...
by OB General Science - guoqingw
Wed May 31, 2023 8:52 am America/New_York
Forum: Questions/Comments
Question: l2gen algorithm - source code error
Replies: 4

Re: l2gen algorithm - source code error

Lachlan is correct. chl1 is the chlorophyll estimated using CI algorithm (the parameters are from Hu et al. 2019) which performs better for low values. Here it was used to find the upper limit for the blending of CI and OCx algorithm to make sure low values are estimated using CI algorithm.
by OB General Science - guoqingw
Tue May 30, 2023 3:50 pm America/New_York
Forum: Questions/Comments
Question: Interpretation of the Aqua-MODIS scene
Replies: 1

Re: Interpretation of the Aqua-MODIS scene

Hi,
That is one of the magic pictures produced by one of our retired scientists.
Here is a thread that he answered questions similar to yours and more:
viewtopic.php?f=7&t=1237

Hope you find it helpful,
Guoqing
by OB General Science - guoqingw
Tue May 30, 2023 1:03 pm America/New_York
Forum: Questions/Comments
Question: masks & flags : OLCI
Replies: 3

Re: masks & flags : OLCI

Hi Slava,

No. The l2flags are up to date. Can you please provide some details - What are the differences? Did you noticed the differences in an OLCI file? If so, which one?

Thanks,
Guoqing
by OB General Science - guoqingw
Tue May 30, 2023 11:45 am America/New_York
Forum: Questions/Comments
Question: MODISA Level 3 Mask question
Replies: 1

Re: MODISA Level 3 Mask question

Sorry for the delayed response. There is no flag information on level 3 data. As binned data from level 2, level 3 data only used l2flags for quality control purpose in the binning procedure. Here are some documents that you can refer to about the details: https://oceancolor.gsfc.nasa.gov/atbd/sst/f...
by OB General Science - guoqingw
Wed May 24, 2023 4:04 pm America/New_York
Forum: Questions/Comments
Question: Global valid observations of ocean color products
Replies: 1

Re: Global valid observations of ocean color products

Hello, The pattern doesn't make sense to me, and this shouldn't be a problem with the products. But just in case, can you please provide more details about what you did? Did you use the whole dataset (all the available l3 Chlorophyll products) for each mission to calculate the ratio? Is the ratio ca...
by OB General Science - guoqingw
Thu May 18, 2023 12:47 pm America/New_York
Forum: Questions/Comments
Question: Chla-historical data
Replies: 1

Re: Chla-historical data

Hi Nabila,

Yes, we provide both in situ and satellite Chlorophyll-a data. Please let me know which one you are looking for. The methods to access them are a little bit different.

Guoqing
by OB General Science - guoqingw
Wed May 03, 2023 2:56 pm America/New_York
Forum: Questions/Comments
Question: Different value of MODIS Data
Replies: 1

Re: Different value of MODIS Data

Hello, The difference is a likely result. When you use the average of the whole region for the trend, the value is more likely to be consistent. But if you take a closer look at the region for a particular day, as what you do in the first figure, you'll see the data vary from coastal water to the se...