Questions tagged [remote-sensing]

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

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3
votes
1answer
54 views

What is the technical term for spatially aggregated measures?

Is there an adjective to describe data that has areal weight, like area, biomass, population, etc. — data that has to be aggregated by sum for example — vs. data that doesn't, such as landcover ...
6
votes
2answers
81 views

Observations of sea ice typology in the Arctic

What are the main datasets characterizing sea ice typology, thickness, density, "passability", presence of pressure ridges in the Arctic? Is it something that can be detected from the air or a space ...
5
votes
1answer
82 views

Remote Sensing System (RSS) historical atmospheric data continually updated

Does anyone know why every month there are updates to the RSS historical atmospheric data? How can data that is 10 years old need adjusting every month? For instance, here's the difference in data ...
6
votes
0answers
78 views

Spatial variability in ocean surface winds

For the near-surface winds over the ocean, many model products and satellite footprints have spatial resolutions on the order of tens of kilometers. I'm interested in knowing how much the winds (both ...
5
votes
1answer
559 views

Should Modis & LandSAT NDVI composites agree and why not?

Modis takes daily images at coarse resolution (500m?) that are then lumped into 16-day composites. LandSAT, let's say 8, takes roughly bi-weekly images at 30m (100m resampled to 30), and those are ...
7
votes
1answer
2k views

How to count lightning in a thunderstorm?

Is there an accurate way to count the amount of lightning happening in a thunderstorm? How is lightning measured? Is there a special unit for this?
4
votes
1answer
278 views

What is the purpose of this large structure on a Japanese hillside? [closed]

A Google satellite view shows an unusual structure on a hillside in Miyazaki Prefecture, Japan (Latitude 31.782600°N, Longitude 131.233881°E): It measures about 170m by 120m and is structured in ...
11
votes
2answers
2k views

What color is the Sahara desert, as seen from orbit?

In images of the Earth taken from spacecraft (or composite images thereof), the color rendering seems to be really inconsistent. Examples (Source: NASA, http://visibleearth.nasa.gov/view.php?id=...
7
votes
2answers
262 views

Predicting earthquakes using disturbances in DTH TV transmission

It is said that before an earthquake happens, a viewer experiences disturbances in DTH TV transmission in the form of distorted images on the screen which automatically correct after a few seconds. ...
5
votes
1answer
587 views

Locating Missing Airplanes using Remote-Sensing Satellites

The Maylaysian jetliner that went missing has yet to be found. There are many remote sensing satellites, equipped with radars, currently in service. Together, they provide good coverage of the entire ...
8
votes
1answer
546 views

What is a Geophysical Model Function (GMF)?

I have heard the term mentioned many times in seminars, and in papers on remote sensing. What does it mean? References would be helpful if available.
8
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2answers
226 views

TRMM rainfall measurement for synoptic systems

I have gone through the website of TRMM that explains how the TRMM satellite gather precipitation data- http://pmm.nasa.gov/node/158. During the Indian Summer Monsoon (ISM), we have synoptic systems ...
7
votes
0answers
192 views

NASA GLAS Lidar Data Format [closed]

NASA GLAS Lidar Data can be downloaded here. I cannot find (or perhaps understand) the answer to my question on the icesat/glas page. Lidar data can be provided as points (las) or raster (dem), ...
9
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1answer
300 views

What sort of instruments do planetary geologists use to predict that there are oceans on the moons Titan and Europa?

NASA Planetary Scientists released a video that says they have confirmed that there is an underground ocean in Europa and that Titan has liquid oceans made of hydrocarbons. I myself am an aspiring ...
7
votes
1answer
364 views

What are the advantages in looking at an OLR map versus looking at IR satellite imagery?

Conceptually they seem to be showing the same information. But in the context of a Madden Julien Oscillation (MJO) or equatorial waves especially over the equatorial oceanic layers which one is more ...
8
votes
0answers
78 views

Iowa State GOES Visible Data - misaligned EPSG:4326

The WMS server of Iowa State is serving data for the GOES-13 satellite in the visible channel. As best as I can tell, the data is misaligned with other data sources. For example, in a WMS client, ...
19
votes
2answers
390 views

To what accuracy and precision do we know the volume of the Earth?

Satellites such as GOCE and GRACE measure the geoid with unprecedented accuracy. Altimeters can determine local surface elevation with millimetre-precision. This makes me wonder: to what precision ...
13
votes
1answer
98 views

GOES Visible Channel - asymmetry between morning and afternoon

In the GOES-13 Visible channel, there seems to be a morning/afternoon asymmetry in the data. I'm wondering what might cause this. In this example data, the morning is the lower branch, and the ...
11
votes
1answer
600 views

Are the elements of an averaging kernel matrix always centered on the diagonal, or can they be exclusively off-diagonal in rare cases?

According to Rodgers (2000) equation 2.80 $$ d_s = \mathrm{tr}(\mathbf{A}) $$ where $d_s$ is the number of degrees of freedom for the signal, tr denotes the trace, and $A$ is the averaging kernel ...
10
votes
3answers
2k views

What geophysical instruments should I use to detect water without drilling?

How can one detect (preferably artesian) aquifers nowadays that a lot of sensors are available? Should I use ground-penetrating radars, neutron detectors, or any other advanced devices? Can seismic ...
14
votes
1answer
180 views

What kinds of remote sensing required to observe methanogenic life on Titan?

Inspired by Chris McKay's Possibilities for methanogenic life in liquid methane on the surface of Titan. In the paper, the PI's found that the consumed acetylene, ethane, and other organic solids ...
22
votes
1answer
543 views

How is ocean salinity measured from space?

Since 2009, two satellites (SMOS from ESA and Aquarius from NASA) are providing global salinity measurements. While ocean temperature is easily derived from infrared radiation for instance, what ...
16
votes
2answers
784 views

How does remote sensing of ocean currents work?

I am aware that techniques exist for measuring surface currents using HF radar, either from land-based installations or from space. How do these work? I have assumed in the past that it's some sort ...
10
votes
1answer
113 views

What methods exist for remote profiling of oceanic columns?

Remote sounding of the atmosphere is a well-established method used extensively used extensively for operational weather forecasting and scientific research. Active or passive instruments carried on ...

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