A message from our CEO about the future of Stack Overflow and Stack Exchange. Read now.

Questions tagged [remote-sensing]

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

Filter by
Sorted by
Tagged with
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 ...
19
votes
3answers
6k views

Why clouds are not moving in NASA's video of the Moon passing in front of the Earth?

I recently saw a short video from NASA. It shows the moon passing by the Earth as it rotates. NASA link: From a Million Miles Away, NASA Camera Shows Moon Crossing Face of Earth. The video itself ...
19
votes
2answers
381 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 ...
16
votes
2answers
774 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 ...
14
votes
1answer
179 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 ...
13
votes
1answer
97 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
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=...
11
votes
2answers
260 views

How to remove 'silk braid' noise in satellite data?

Satellite remote sensing data is a powerful tool for researching the spatial distribution and temporal variation of atmospheric species. Aura is one satellite owing to NASA which meaning ...
11
votes
1answer
594 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 ...
10
votes
2answers
168 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 $NH_3$-...
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 ...
9
votes
1answer
298 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 ...
8
votes
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 ...
8
votes
1answer
329 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 ...
8
votes
1answer
540 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
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, ...
7
votes
2answers
430 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 ...
7
votes
2answers
393 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, ...
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. ...
7
votes
1answer
363 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 ...
7
votes
1answer
188 views

Need help understanding this satellite image of Larson C ice shelf

The false color image below shows synthetic aperture radar imaging from ESA's Sentinel-1 satellite. The map from the 20-Jan-2017 BBC article Larsen ice crack continues to open up illustrates the same ...
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?
7
votes
0answers
191 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), ...
6
votes
1answer
145 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 ...
6
votes
3answers
953 views

Can you measure BOD/COD real time using any sensor?

There is a requirement to measure BOD/COD in a wastewater treatment plant in real time. Is it possible? And if so are there any sensors available in the market for it? COD: Chemical Oxygen Demand BOD:...
6
votes
1answer
220 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 ...
6
votes
1answer
106 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 ...
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 ...
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
585 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 ...
5
votes
2answers
154 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 ...
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 ...
5
votes
1answer
116 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 ...
5
votes
1answer
558 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 ...
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 ...
4
votes
2answers
81 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 ...
4
votes
1answer
452 views

Methane remote sensing?

I'm trying to compile a list of remote sensing (Earth observing satellite) instruments capable of detecting methane in the atmosphere or near surface of Earth. After some search I have found: ...
4
votes
1answer
40 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 ...
4
votes
1answer
306 views

What is principle of inverse modeling?

I read a few paper related to emission inventory talking about the inverse modeling. It was another method to estimate the emission from ground(called top-down ...
4
votes
1answer
69 views

The higher value range for the same satellite product (NO2_OMI_TEMIS)

I'm dealing with NO2 column density of troposphere, and my data source is TEMIS. The NO2 level3 data can be derived from the original information of OMI instrument. I have downloaded two types of ...
4
votes
2answers
127 views

Need help understanding variables that relate to meterology terminology

I am working on a project in predicting the weather and I had a few brief questions. I understand that radar works by bouncing waves off of precipitation and measuring reflectivity. I have a variable ...
4
votes
0answers
124 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, ...
4
votes
0answers
123 views

Software and methods used in LIDAR data visualization?

I was assigned a task to prepare a report which states the current state of the art in Doppler wind LIDAR (DWL) visualization and visualization tools used in meteorology. In the last 3 days I've tried ...
3
votes
2answers
107 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 ...
3
votes
1answer
637 views

How do weather services measure wind

I'm curious to know where commercial weather services like the Weather Channel and Weather Underground get their wind speed and direction measurements, to produce maps like this one (http://www....
3
votes
2answers
120 views

What is a breadboard (retrieval) algorithm in the context of geophysical satellite retrievals/remote sensing?

In a recent met-jobs job posting (different version here) for a researcher with a background in climatology/meteorology/hydrology or environmental sciences, I saw the phrase breadboard retrieval ...
3
votes
1answer
78 views

GIMMS NDVI3g grid cells not entirely square-shaped?

The official data description of the recently updated GIMMS NDVI3g record describes the grid parameters of the dataset as follows. ...
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 ...
3
votes
1answer
833 views

Convert OMI NO2 Vertical Column Density (molecules/cm^2) into Mixing Ratio (ppm)

I want to convert OMI AURA data on NO2 column amounts in molecules/cm2 into ppm for comparison purposes with other literature. Can it be done? Is there a standard way of doing it? I looked into the ...