Questions tagged [measurements]

Questions related to acquiring, processing and interpreting field measurements of any kind. Including instrumentation and data analysis.

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6
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1answer
1k views

How do scientists measure the age of old animal remains?

The remains of a mammoth were recently unearthed in a Michigan farmer’s field [1]. This find could provide new information on the activity of early humans in the area, experts at the University of ...
6
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1answer
281 views

Unwarranted claim of higher degree of accuracy in zircon geochronology

The uncertainty in the half life of uranium-238 is stated at 0.05% [1]. The same paper gives the date 251.941 myr ± 31 kyr. 251.941 $\times$ 0.05% = 125 kyr. How are the authors justified in ...
6
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1answer
1k views

Is there a way to calculate the ground and 10m temperature from standard 2m temperature measurements?

I am wondering if it is possible at all to calculate the ground temperature and air temperature at 10m above ground from 2m measurements, or at least using data that a standard weather station ...
6
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1answer
794 views

How accurately can a tsunami be predicted? Have there been any successful evacuations?

With the current instruments in hand, how accurately can we predict tsunamis? Please consider me as a novice with only basic information how tsunamis are formed. Has there ever been a successful ...
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69 views

High-resolution laterolog array tool

Does anybody know if it is necessary to apply corrections to the reading given by this logging tool? Corrections such as bed thickness, borehole diameter, invasion, etc.? If so, is there anywhere I ...
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89 views

What, if any, scientific value do global soundscapes have?

Seems like the Earth Day related crowd sourcing project to create the first global soundscape by encouraging smartphone owners around the world to download and use an app developed to record the ...
5
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2answers
948 views

Is there a difference between Density and Specific Gravity?

My textbook says that the specific gravity is "the ratio of the mass of a mineral compared with the mass of an equal volume of water." Is this any different to density? If so, how? If not, why does ...
5
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4answers
160 views

What are the technical solutions to measure $\ce{CO2}$ emissions?

I'm currently at COP24 (United Nations Climate Change Conference) in Katowice, Poland. (some editing since I took a screenshot of my laptop) I've asked some guys about $\ce{CO2}$ emissions but very ...
5
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1answer
898 views

Where can I get historic hourly precipitation data for Italy?

I am looking for a time-series of hourly precipitation for Naples, Italy. I'd like to learn how to find this sort of data for Italy in general, as well. Ideally this data would cover a recent year ...
5
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1answer
599 views

How to determine that sustained wind speed exceeded the threshold value?

Certain maritime ports and airports have ranges of operation relation to the wind, usually according to a given threshold value of sustained wind speed. If I have the instantaneous values from ...
5
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1answer
112 views

How is relative humidity determined from a wet and dry bulb readings?

The question What is the second thermometer in the image from the Esperanza Antarctic temperature record? shows what might be a wet/dry bulb setup. I've given one to a friend to measure humidity for ...
5
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1answer
743 views

How to make, read, and calibrate a ping-pong ball anemometer?

I'd like to make a ping-pong ball anemometer to make estimates or approximate measurements of wind and surface air currents at low to moderate speeds. I don't own an anemometer now, but I'd estimate ...
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1answer
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How to find Cloud cover data in GFS grib models

I've been looking for the cloud cover estimates provided in the NOAA GFS models. This page discusses all their weather products and one of the few I find that includes cloud cover data "Total Cloud ...
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176 views

Was the “'Bama Boom” even recorded by infrasound or by seismic detectors?

The 'Bama Boom ('Bama is short for the US state of Alabama) is a term for some audible "booms" heard by many people in Alabama and now in Colorado. See for example the Popular Mechanics article ...
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142 views

How are global cloud cover estimates generated and how is the data accessed?

The website ventusky.com offers three models to produce cloud estimate: ICON, GFS and GEM. They extract a fractional cloud number, shown in percentage. From the ERDDAP portal to the GFS model (...
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2answers
8k views

How can we measure the thickness of the Earth's mantle? [duplicate]

According to Wikipedia the earth's mantle is approximately 2900 km (1,800 miles) thick. How is it possible to achieve such measurements? Obviously we haven't sent anything down that far to check.
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179 views

How many days has it been since the Cambrian explosion?

I want to know how to calculate the number of days since an event in Earth's past, and am using the Cambrian explosion as an example. I define a day to be one rotation of Earth with respect to the ...
4
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1answer
91 views

What is the second thermometer in the image from the Esperanza Antarctic temperature record?

Today, the Argentinian meteorological service tweeted about a new temperature record for Antarctica of 18.3°C, made on the Espezanza peninsula. This was subsequently reported by many other sources. ...
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1answer
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How does one interpret negative geopotential height values?

I am using NCEP Reanalysis Geopotential height data and this is at 1000 mb and downloading it from here - 1000 Mb Geopotential height values and some of these values are negative for a particular date ...
4
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1answer
75 views

Is there a concise industry standard way of displaying wind speed, gust and direction?

I'm writing a smart-watch watch-face app with weather details. Since it's on a 1"x1" screen, I'm trying to keep all information as compact as possible. I'm using open weather map for my testing, and ...
4
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3answers
78 views

How is land subsidence measured?

When groundwater is pumped out of the ground by wells, and not replenished fast enough, the groundwater level sinks. With it, the surface of the area sinks also. Locally, this effect is not apparent,...
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1answer
108 views

How does NASA get a 360 degrees texture map of Earth?

How does NASA get a 360 degrees texture map of Earth and separates it into specularity map, bump map etc? And how do they get the texture map of clouds separate?
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1answer
85 views

What causes variation of seabed depth relative to fixed chart datum?

Please refer to this page of coastal wiki. Quoting: ...the reconstructed overall vertical position [of the seabed] with respect to a fixed chart datum may vary by more than 10 cm from survey to ...
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85 views

Extent of desert area influence in local climate

With reference to this image...: ...from this recent tweet, I was wondering to what extent would Mediterranean regions be affected by the large desert areas to its South? "Affected", here meaning ...
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234 views

What does a floating mercury barometer look like? How does it work and how is buoyancy used?

This answer to How are barometric pressure measurements traceable over centuries to 100 parts per million accuracy? describes a floating mercury barometer, and mentions that some employed a Vernier ...
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102 views

How temperature anomaly are measured

Temperature Anomaly is the measure used to show that the earth is warming. The formula for temperature anomaly involves in the subtraction of average temperature measurement over 30 years considered ...
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2answers
4k views

What is the meaning of the units Mg C?

I am reading an article on deforestation entitled Tropical Deforestation and Carbon Emissions from PADDD. Part of the article reads: If future deforestation rates follow recent trends, PADDDed ...
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1answer
63 views

Measuring the circumference of the earth - revisited

I have done a bit of research on this topic already and the easiest way seems to be the experiment by Eratosthenes. We pick two locations on the same latitude (of which we know the distance) and then ...
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1answer
206 views

Are there “transparent” clouds?

Comments below this answer to the question Why are lightning towers at launch pads topped with big hollow tubes with spiral windings and not “lightning rod-shaped” lightning rods? link to a 2013 ...
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2answers
563 views

What was the lowest temperature ever recorded on the surface of Earth?

This article Lowest recorded temperatures lists a -89 Degrees Celsius in Vostok, Antartica as the lowest recorded temperature. However, this other article List of weather records lists a −93.2 °C (−...
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1answer
474 views

Accurately Measuring Indoor/Outdoor Air Temperature & Relative Humidity

I’m conducting an independent study as a concerned citizen on the indoor temperature at an animal shelter to support the need of improved air conditioning by documenting how hot it can reach during ...
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1answer
169 views

What kind of climate could you expect in a mountainous area in a subtropical region?

More specifically, I'm trying to work out climate analogues for my farm. It's at 5200-6200ft in South India. My area is a bit too small for the Köppen Map to correctly reveal patterns. I'll be ...
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34 views

Where to find meteorological data from road stations?

I am involved on a project that aims to analyze data from road weather stations, like the ones you can see from a German site here: https://www.dwd.de/EN/ourservices/bufr_extensions_national/...
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63 views

Is there a sort of “global natural disaster” index?

Is there what could be called a "global disaster index", i.e., a measure of the number, weighted by their intensities, of all the world's natural disasters at given moments in time throughout history?
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423 views

Trewartha climate classification overlap?

By my reading of the wikipedia page on the Trewartha climate classification, climate classifications are not mutually exclusive. Let's take a look at the climate classification of Iowa City, IA. The ...
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0answers
54 views

Capillary rise experiment and obtainable information about the porous medium

I have access to rock core(s) and vacuum saturation chambers as seen in the image below. I can dry the rock core using an oven, measure its geometry and mass. I can place it into the vacuum ...
3
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1answer
278 views

How accurate are the resistivity values from the electrical resistivity tomography (ERT)?

Modern ERT methods/devices can provide 2D resistivity profiles for some terrain. How accurate are the resistivity values in those profiles? Are these some sorts of apparent resistivities and one ...
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0answers
138 views

Desert greening - Do we have long term (several decades) data on precipitation around the Sahara?

This article of desert greening states that some areas around the Sahara have seen increased plant growth in recent decades, caused by global warming. The causal chain would be warmer air can hold ...
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0answers
43 views

Conversion factor between different Landsats?

I have collected data (spectral bands) from Landsat 4-5 and Landsat 8. I was calculating NDVI when I noticed that the two Landsats have different band numbers designated as Red and Near Infra Red (...
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0answers
745 views

Determine Latitude and Longitude without a GPS [closed]

Is it possible to measure the strength of a rare earth magnet to determine latitude and longitude of a current position? For instance say you start with your known latitude and longitude and then use ...
2
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1answer
68 views

If the accuracy of measurement of the earth's volume is not known, how can scientists assert that the earth is not expanding?

Volcanic eruptions, undersea earthquakes, fissures in the crust, meteoroid accumulation could all be seen as empirical evidence of expansion of the earth. Sink holes and other phenomena could be ...
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3answers
3k views

Difference between Meteosat and Insat satellite Images

I have seen many times that their are two kinds of Satellite Images shown on the websites like Skymet for India i.e. Meteosat satellite images Insat satellite images I want to understand the basic ...
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2answers
79 views

Data for plotting tephigrams

I want to plot some tephigrams. Where can I find pressure, temperature and dewpoint data in text format?
2
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1answer
82 views

Atmospheric visibility measuring device

I have this project at university where I have to make an atmospheric visibility measuring device using Arduino. I talked with my teacher and he said that I should do something like this, using an ...
2
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2answers
340 views

How is surface pressure generally measured, and at what actual height?

In various atmospheric equations, surface pressure is one of the variables used. For example, in calculating the density of air or pressure-corrected relative optical air mass. How is surface pressure ...
2
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1answer
172 views

How does MSLP change with elevation? trying to interpolate MSLP

My understanding of MSLP is that it is a normalized value for pressure at some location as if that location altitude was zero. "Thus, MSLP is not a function of elevation" However, after inspecting ...
2
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1answer
513 views

What is the distribution of global photosynthesis?

Has anyone attempted to classify global photosynthesis? For example, what percentage of it occurs over land? What percentage comes from agriculture? Same questions for total growth of plant mass. ...
2
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1answer
60 views

Does the length of a river depend on the scale of measurements?

Coastlines are highly fractal, leading to the coastline paradox: the length increases to surprisingly large numbers as your scale of measurement gets smaller. Does the same thing apply to rivers, ...
2
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1answer
61 views

Transmitter receiver coil separation for Electromagnetic Terrain Conductivity Measurement

Why increasing transmitter-receiver coil separation in EM survey (EM31, also here) increases depth of penetration? Suppose there is a horizontal flat conductive layer underneath a flat resistive ...
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2answers
220 views

How are daily precipitation totals computed?

I would like to use ASOS data from Iowa State University to compute daily rainfall totals for specific locations. Using ASOS, I am unable to match the official NWS totals. I am assuming that the ...