Questions tagged [remote-sensing]

Questions about measurements which are taken from remote locations / are not taken in situ.

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13 views

Where do I access Landsat 5 TM from 2002-08-04 to 2008-06-01

I am searching for Landsat 5 TM images from 2000 to 2012 in the Earth Explorer Web site (https://earthexplorer.usgs.gov/). However, I couldn't find any scene in my study area starting from 2002-08-04 ...
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25 views

How can I relate aerosol particle size (2, 5 and 10 microns) with the aerosol index measurement of the Sentinel-5P (TROPOMI) data sets?

I would like to know the relation of aerosol particle size (2,5 and 10 microns) with the measurements from the Sentinel-5P TROPOMI data, in the wavelengths 340-380 and 358-388 nm bands.
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35 views

What are those precipitation and water droplet characterization instruments called that they put on meteorological aircraft? How do they work?

A long time ago I did some reading on Mie scattering and atmospheric particulate counting and I got sidetracked on raindrop characterization. I remember reading about light and laser based ...
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56 views

Normalized Difference Vegetation Index sensitivity to soil

A lot of papers mention that Normalized Difference Vegetation Index (NDVI) is sensitive to soil background such as bare soil. My question is what is the exact reason behind the impact of soil on NDVI? ...
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45 views

Why does SNAP let me open some Sentinel-5p products and not others?

Good morning, I am working with Sentinel-5p products, my final thesis is to establish a methodology for processing this type of images, from downloading to the implementation of a colour map with the ...
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173 views

How do I convert Sentinel-5p / TROPOMI vertical column density to concentration?

I am doing an study on Sentinel-5p TROPOMI images. I would like to convert the data from mole/m2 to μg/m3, for this I know I need the height data of the measurements. I have looked for them and I have ...
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1answer
270 views

Can I regard the grayscale of a RGB color image as a panchromatic image?

Here I have a remote sensing dataset with many bands (e.g., blue, green, red, ...), and I use the blue, green and red bands to get a true color image. I want to know if I can get a panchromatic band ...
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1answer
62 views

Is there any intuitive and easily understandable way to help students understand the triangular facet of outcropted stratigraphy?

I find it difficult to teach college students about using the triangular facet on remote sensing images to judge the dip direction of sedimentary formations. Is there any intuitive way that can help?
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63 views

How can we distinguish fold and cycle of sedimentation on a remote sensing image or in the field?

A fold is composed of stratigraphy that is symmetric and repeated. Cyclic sediments (also called rhythmic sediments) are sequences of sedimentary rocks that are characterised by repetitive patterns of ...
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1answer
81 views

Free periodical satellite/aerial imagery

There is a company called Planet Labs which sells daily satellite imagery covering the whole globe that can be used for various research like agriculture, forestry etc. I wonder if there is a free ...
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1answer
53 views

Is there a name for a type of algorithm or processing which uses only one source of data as input?

Many algorithms in remote sensing take one or more different datasets as inputs and return some output. An example might be computing the amount of sulfur dioxide (SO2) injected into the stratosphere ...
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23 views

Where can I find canopy reflectance data for crops (soybean in particular) for different dates across the growing season

I have been trying to find literature values for reflectance of soybean for different dates along the growing season (I am specifically interested in 30, 60 and ~120 days after planting - so the V3/V4 ...
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59 views

Lead remote sensing?

I am trying to formulate a research topic centered around the environmental effects of general aviation's continued use of leaded gasoline (containing tetraethyllead) to power piston aircraft. In ...
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1answer
558 views

How to convert mol/m^2 to total mass ( e.g gram, kg etc )?

I want to calculate the total $\rm{NO_2}$ amount in a year using satellite Sentinel-5p NO2 dataset. But the problem is sentinel satellite data stored in $\rm\frac{mol}{m^2}$ unit. But I have to ...
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1answer
138 views

Landsat 8 acquisition time and date

The the meta data text file that comes with Landsat scenes, contains an acquisition date and a scene center time in successive lines. I wanted to know if the image is recorded at the scene center time ...
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1answer
192 views

What is the use of HV or VH polarization in Radar?

Radar is a common tool in remote sensing, it is a so-called active instrument, hence it emits and receives energy. Modern Syntethic Aperture Radar (SAR) systems are capable of both transmitting and ...
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39 views

NDWI from Landsat 8

I have layer stacked Landsat 8 image, how can I calculate Normalized difference water index (NDWI) from it? I would have been able to calculate it easily using the raster calculator, if I had the ...
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39 views

Planetary Reflectance vs Relative Spectral Response

I am confused between a Planetary Reflectance and the Relative Spectral Response (RSR). What I know/guess is that RSR is a response/function of an Instrument band's reflectance against a spectral ...
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222 views

How do the pros measure humidity?

I have used a wet/dry bulb setup to estimate humidity, and it appears that the Argentinian meteorological service uses one in Antarctica as well. Wikipedia sez: Humidity measurement is among the ...
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53 views

District/province wise air quality data for South Asia (2010 onward)

I would like to create a district/province-level air quality data for all the countries in South Asia from 2010 onward using satellite data. As someone with absolutely zero background in remote-...
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2answers
267 views

What are the differences between down-looking and side looking radar?

In Radar concept the SAR-Synthetic Aperture radar performs as side-looking to collect information, why it is not downlooking? There are down-looking radar also. So what are the differences between ...
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33 views

Pansharpening of Spot 6 image

Would the pansharpening of Spot 6 work on the NIR band? Since the wavelengths captured by the panchromatic band does not overlap with the NIR band. The band designations are in the attached image.
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50 views

Google earth historical imagery date

I am working on a small creek in Colorado using historical imagery via Google earth. I want to know if the imagery date at the bottom of each image on google earth is the date the google acquired the ...
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20 views

What is the meaning of nomalized difference Built-up index?

I know how to calculate it by remote sensing image, but why do we define this? What can we know about a remote sensing scene by this indicator? What's the connection between normalized difference ...
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1answer
35 views

Regional and Relative Sea level

I am a little confused by the terms "regional" and "relative" in the sea level change context. Do the two words have the same meaning? Does the "regional MSL trend" in https://www.aviso.altimetry.fr/...
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48 views

How to transform level 2 satellite retrievals to level 3 gridded data

Usually, I use level-3 gridded satellite data to analyze the spatial and temporal patterns of atmospheric compositions. However, there were some data sources which only afford level 2 product. For ...
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What (if any) "in-situ instrumentation" is on the Brunt Ice Shelf that will detect its splitting and breaking away?

The BBC News article Antarctic: No role for climate in Halley iceberg splitting says: With no-one on the ice surface, notice of any breakaway will have to come from automated in-situ ...
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1answer
200 views

Public sources of topographical data of Earth?

I would like to find sources of topographical data for Earth's surface. I've looked in GIS SE and Open Data SE but haven't found a good answer to this so I though I'd ask here in Earth Science. Are ...
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1answer
48 views

What is the most real-time method of determining SPI?

For drought monitoring related to vegetation, I need to calculate Standardized Percipitation INdex for a given area. Where can I find the most real-time percipitation data to do this? The best I've ...
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1answer
65 views

Where can I find archived night microphysics images from EUMETSAT? I

I want night microphysics RGB composite from EUMETSAT. I'm looking for archived images. I tried finding them on EUMETSAT's data center page. Data from different channels of SEVIRI is available but ...
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1answer
427 views

How to extract lat-lon from MOD10C2 hdf data in matlab?

We can import and read all given bands/parameters of MOD10C2, lat and lon is not given as separate band rather embedded with other bands. How we can extract from MOD10C2 hdf data in matlab. Similar ...
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1answer
103 views

How to figure the MODIS snow cover against different elevation zones?

I am working on MOD10C2 (8days snow cover), when I clip the MODIS snow cover against different zones of elevation the results was against general trend .i.e. the higher elevation was showing lower ...
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1answer
57 views

Artefacts in PERSIANN-CCS data

I downloaded PERSIANN-CCS for the region of Pawlowdar, Kazakhstan and this has stripes all over my downloaded data. For another AOI in Kazakhstan I do not have this problem. Does anyone of you have ...
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1answer
610 views

Why is satellite imagery data delivered as signed 16 bit integers?

Landsat 5 tm reflectance product images are delivered as signed 16 bit images, why is this preferred to unsigned 8 bit that the DN's are stored as level 1 products for the same satellite? Look at ...
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1answer
86 views

Satellite image displaying as panchromatic

I have a 4 band image (Blue, Green, Red and Near Infrared). If I display my image with only the green band in the RGB channel, the image displayed is panchromatic. Why is that?
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2answers
680 views

How does ice-penetrating radar "see" through kilometers of ice without being absorbed?

The BBC News article Isolated lakes found beneath Canadian ice sheet links to the open access Science Advances article Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, ...
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28 views

Detecting the hydrothermal alteration zones?

Is it possible to use remote sensing to determine Hydrothermal alteration zones without resorting to collecting samples from the Area of study?
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204 views

A rough picture about the ground-level ammonia (NH3)

Ammonia is the only alkaline gas in the atmosphere. It is one of the key features to control the acidity of aerosols and the formation of ammonium salts. In the environment of $NH_3$-rich and $NH_3$-...
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1answer
41 views

What is an 'obstacle vista diagram'?

Currently I do some research about SODAR and at this paper, the author wrote (p. 1502f): A site should be relatively clear of obstacles that could act as potential fixed-echo reflectors. If that ...
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1answer
133 views

Are there standards for tropospheric NO2 levels considered low or high?

I'm working with Ozone Monitoring Instrument (OMI) $\ce{NO_2}$ vertical column density (molecules/cm2) data. To help interpret the values, I'm wondering if there are standards that show which values ...
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2answers
624 views

How do optical satellites detect different leaf types?

In various land cover classification systems, trees are also categorised on the basis of broadleaf or needleleaf. Can someone please tell me the mechanism through which satellites detect this leaf ...
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1answer
77 views

Using NASA's radiance calculator to make a graph to find the where the peak radiation emission are?

I am trying to graphically show the radiance emissions of both the Sun and Earth. I am using NASA's radiance calculator then going to graph it on paper. Here is what I typed in: Low wavelength: 0....
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149 views

How to read EUMETCAST GOME-2 data?

We receive EUMETCAST data with different formats in our local station, I am having the most difficulty when trying to read or sometimes even know the format of a specific data product, in this case, ...
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1answer
126 views

Satellite ocean near-surface air temperature data

For my study, I need to use satellite Sea Surface Temperature (SST) and at the same time I also need satellite air temperature data (Ta) for the first few meters above the ocean. For SST I'll be ...
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1answer
421 views

Understanding pushbroom sensors

Does a push broom scanner scan a path perpendicular to the direction of satellite travel? I am confused because its detectors are arranged across track even though it scans along track.
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1answer
107 views

How to get single value of NDVI value from four different directions?

I have a data set which contains NDVI (Normalized Difference Vegetation Index) values of four directions (NE, NW, SE, SW). Now, I would like to have single value which considers all 4 directions. Is ...
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383 views

The giant 6,000 km$^2$ iceberg A-68; will ground-truth telemetry supplement satellite tracking data?

update 2: FIRST images of A-68 iceberg not taken from a satellite in space but from the air are out. On this NASA Earth Observatory web page are areal images from NASA's Operation IceBridge taken from ...
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2answers
109 views

Odd Inuksuk-like objects

I found some huge objects that are way too big to be inuksuks, in my opinion. The object on the right is very odd because the arms are not straight like they are in most images of inuksuks. and ...
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82 views

Calculating band depth image for M3 data

I am working with chandrayaan M3 hyper spectral data. I need to create a band depth image for identifying mineral abundances. How do i calculate the continuum reflectance value for producing a band ...
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2answers
191 views

MODIS Surface Reflectance Data State QA Aerosol Quantity field meaning is unclear

I am trying to compare NDVI values computed from MODIS Surface Reflectance(MOD09) with the NDVI product (MOD13). MODIS Surface reflectance Collection 5 products include a Data State QA field that I ...