# Tag Info

32

There are many "uncharted waters". Nautical charts have information about water depths, dangers to navigation, aids to navigation, anchorages, and other features. You can see here what might be included in a nautical chart: U.S. Chart No. 1 The area in question is a shallow sea... so boats of different sizes may or may not be able to take certain routes ...

12

Considering that the Mid-Atlantic ridge was just discovered recently (in geological terms), much of the Earth's water is still unmapped. The surface can be easily mapped by satellites, as said by farrenthorpe. It's just undersea territory which remains a deep mystery (no pun intended). Some question the fact that we can estimate the depth of the Mariana ...

11

These are most certainly boundary layer rolls and not gravity waves. While there exists a visual similarity between the two phenomena, and both may exist in similar atmospheric conditions, they can be distinguished by two key characteristics: Unlike gravity waves, which develop in the downwave direction (perpendicular to the crest), boundary layer rolls ...

11

A lot depends on the definition of "charted". How much detail must we know for an area to gain this status? As others have said, we have a low-resolution idea of all of the non-ice-covered seabed from satellite altimetry and gravity measurements - but there is a big difference between this, with a resolution measured in miles, and a high-resolution multibeam ...

10

The structure looks similar to this photograph of a "Japanese land retention system" mentioned in passing towards the bottom of this webpage. From the linked page: Land retention systems in Japan, for example, are often designed as heavy waffle grids which are molded to the topography and cover it to a uniform structural depth. This seems to correspond ...

10

Civilian earth observing SAR satellites do not always operate over empty swaths of oceans (specially in the middle of Indian Ocean) in order to save power. They are not designed to track a fast moving target and have repeat cycle of at least a few days. Then there is the issue of resolution. High res acquisitions modes (with satellites like TerraSAR-X) are ...

7

As the other answer suggests, these are sonar surveys of the ocean depths. But the answer is a bit more complicated. The vast majority of the ocean floor has never been mapped. We really only know about the water depth because the water above the sea floor is lighter than if it were rocks. So a deep ocean produces less gravity than a shallow one. And, ...

6

Yes, mean cloud cover is routinely measured from satellites. Like all satellite data (and in fact all measurements), it does have an uncertainty, but for the purpose of this question the satellite product of mean cloud coverage is good enough. Personally, I would hesitate to trust the data at very high latitudes with frequent cover of snow or ice, because ...

5

You ask, How to remove these abnormal value for more precise data? The short answer is that you might be able to make your data look more representative of the natural 'truth', but you will probably have to pay for this with some precision. The problem is that the measurement itself is imperfect: this looks like an artifact of the data collection method. ...

5

This is just supplemental information to the accepted answer by @gerrit I took the ESA cloud cover fraction map provided there, and added dots that represent the approximate locations of the ground stations shown in the 2014 map shown in the question, just to get a rough idea. I used the extremely cool Submarine Cable Map site to identify the likely fiber ...

5

An RGB image can not be rendered if you only supply information for one color channel. This is because three channels are needed: Red, Green and Blue. Different software will deal with this invalid input in different ways: Some might set the remaining channels as black (i.e. filling with zero values). In that case the resulting image will be monocromatic. In ...

4

This a great example of "self-organization" in a geomorphological system; this one an oscillating system at a fairly large scale. On a much smaller scale, you find similar structures on sand dune surfaces themselves as well as dry dusty dirt roads: Self organization (and its scaling) is a complex process delicately dependent on just a few variables, in the ...

4

Provide a monthly average in every grid cell, and describe how many measurements were used for each cell. There is no fixed rule for the minimum number of days for reporting a monthly average. A reasonable threshold will depend on the geophysical quantity of interest y, in particular on how much y varies on short and long timescales. If y varies from ...

4

These features are internal gravity waves (IGW) and are characterized by alternating areas of upwards and downwards movement of air parcels. They propagate on a sharp density interface between a relatively dry layer ambient air above and a layer of sea water laden air below. When the moist air rises the cloud is formed above the condensation level and ...

4

The paper basically combines multiple datasets to figure out the changes in ice surface elevation and ice thickness at tidal and multi-year timescales. That way they were able to study grounding line migration, and the melt rate of the glacier and its corresponding ice shelf from above and below. Then they were able to make inferences of the processes ...

3

Thanks for @Kwinkunks's answer. I have read this paper. And this figure may explain something important. What I have already done is plotting the original data like the first subplot. From Destriped - v1.02, the noise data can be shown clearly. Adding another figure to indicate the big importance of induced noise. Huge difference there! So, I'...

3

Meteosat:- The Meteosat series of satellites are geostationary meteorological satellites operated by EUMETSAT under the Meteosat Transition Programme (MTP) and the Meteosat Second Generation (MSG) program. INSAT:- INSAT-3D is the first Indian geostationary satellite, equipped with sounder instrument that provides frequent good quality atmospheric profiles ...

3

To my understanding, the question refers to studies which aim to estimate pollutant emission fluxes using satellite retrievals of atmospheric constituents. Mathematically, this means estimating the forcing term in an advection-diffusion-reaction system given a set of tracer observations. How well you can localize the emissions depends on the pollutant: for ...

3

Remember the recent disappearance of the Malaysian Airlines flight 370, assumed lost off the coast of Australia? They could not really begin looking for it without first getting a decent map of the ocean floor. It was "uncharted" for the purpose of that search - for most people, "really deep" is all you need to know for practical purposes, but in this case ...

3

Supplementing Wolfgang's answer, here's a National Oceanographic and Atmospheric Administration story that talks about the appearance of ocean-bottom artifacts: With legions of people around the world now exploring the seafloor, many are noticing locations along the ocean bottom marked by mysterious formations of grid-like artifacts. These formations ...

2

Simple harmonic (SH) long crested cloud waves, commonly seen in windswept skies, occur between adjacent air strata flowing in different directions. One stratum is warmer, with higher humidity, causing cloud formation along the inter-stratum boundary. The simple harmonic wave formations conform to the same physics as the Reynolds U-tube experiment taught in ...

2

The launch was scheduled for 2017 using a DNPER launch vehicle. It seems that the contract contract between Kosmotras and Hisdesat was canceled and that resulted in an uncertain launch date. The satellite has been finished since 2013 and it has been waiting for over 3 years to be launched. Source The dispute between Russia and Ukraine resulted in EU ...

2

Behrenfeld and Falkowski, 1997 have maps of cholorphyll concentration for the entire world on pages 11-13 of the linked paper. The maps are divided by into yearly concentration and seasonal concentration, with the maps filled out from experimental data by two different modeling methods. These maps are in mg C / m$^2$ / year, but they offer the ...

2

It seems that you are concerned that your values in the data go above the max value on the color bar shown in the kml file. I wouldn't worry about that. You are using the "level 3" monthly average product, which by definition is highly quality controlled. For most of the globe, typical values will vary between 1 x 10^14 and 5 x 10^15 molec/cm2. Values ...

2

Assuming a well has a diameter of 2 metres, even 5 metres. This would be an exceedingly small target area for a satellite, some hundreds to thousands of kilometres above the Earth to find. Being buried, particularly at 200 metres depth, increases the difficulty exponentially. Satellites are better at finding minerals on the surface, or just below the ...

2

Those blue colors are basically artefacts due to image processing. The last one in Bing Maps doesn't look blue at all. It's just somehow slightly darker with some trees or large animals. The local change of color might be caused by humidity (maybe a seasonal pond) or animals, or both - if animals come to drink. Interestingly, there are similar shapes in ...

1

I don't exactly know what are you looking for, but based my own wild guess and hopefully you will be able to get your Landsat data (ready for analysis) from earth-science. https://search.earthdata.nasa.gov/search/granules?p=C1452914042-USGS_EROS&tl=1532843869!4!!&q=Landsat&ok=Landsat cheers

1

Short answer: yes. The Radiance to Reflectance correction described in the Handbook is just physics based. Therefore, it is valid for any Earth observing satellite. However, the mean solar exo-atmospheric irradiances (table 5-2) are specific to the wavelength bands of the ETM+ sensor. Therefore, if you want to correct other bands you would need new ...

1

Identification of snow in satellite images is done using multiwavelength measurements and including ancillary information. Snow obviously has far more reflectivity compared to barren soil, water or vegetation and any edge identification algorithm on visible channel images will identify their extent. The biggest trouble comes from clouds which can appear as ...

1

For surface data, a good place to start is Intermagnet, a global network of geomagnetic observatories. Their data download page lets you filter by time span and region, and sample rates down to the second are available for some observatories. The data are direct observations from individual observatories at fixed locations, and are not averaged over a region....

Only top voted, non community-wiki answers of a minimum length are eligible