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Rain gauges

1.1. Principles: Rain gauges should have a sharp edge so and near vertical sides on the inside to minimize rainsplash (drops are either in or out); should have a funnel with a small hole to minimize evaporation losses; sides and funnel should be smooth, hydrophobic material to minimize loss due to wetting of the surfaces conducting water. Standard height in the U.S. is about 75 cm (30 inches). In winter the funnel is typically removed so snow doesn’t accumulate on the funnel. Some gauges are heated in winter to melt and measure snow, but this causes some evaporation losses.

Biggest issue is wind, as the turbulence causes undercatch; much more severe for snow. Most common shields to minimize this problem are an Alter (strips of metal hanging around the perimeter) shield and a Nipher shield (like the opening of a tuba); latter will cause overcatch in rain and hail.

Ideal location is in a forest opening to minimize wind effects. Gauge should be located at a distance that is twice the height of the nearest object, which is an angle of 30 degrees from the top of the object (i.e., 60 m from a 30-m tall tree). If necessary, an angle of 45 degrees is acceptable.

Wind effects can be minimized by installing the opening of the gauge at or near ground level, but this makes it harder to service and more susceptible to materials falling into the gauge and possible clogging it, such as leaves.

1.2. Types: standard rain gage gives total. To get the desired accuracy, the water is typically funneled into a smaller tube inside the gauge that is only 10% of the area of the rain gauge. This 10-fold increase allows precipitation to be measured to the nearest 0.1 mm or 0.01 inches.

1.3. Recording rain gauges provide data on rainfall intensity, and these include weighing buckets, tipping buckets, a siphon gauge recording on a chart, or a storage gauge with a pressure transducer.

Temperature

2.1. Principles. Measurements need to be made in a location that is representative. In most cases this means in a shaded area that is not subject to excessive heating or reflected radiation, such as a grassy area. The thermometer needs to be in a shelter that is painted white and well ventilated so it does not heat up as a result of solar radiation. Traditional wooden shelters have a double roof to minimize heating, and they always open to the north in the northern hemisphere to avoid the sun shining on the thermometers at any time when observations are being made. Electronic thermometers are typically put into a stacked-plate type shelter. All shelters can result in temperatures that are too high under conditions of high radiation loads and no wind; biggest problem is after a fresh snow because of the very high albedo.

2.2. Mechanical measurements all based on principle that higher temperature leads to expansion.

2.2.1. Traditionally liquid-in-glass (=thermometers); usually mercury or alcohol;

Bulb or reservoir and then a narrow tube, so small change in volume leads to a a large change in distance; read directly off the scale for regular thermometer;

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Field measurements in hydrology. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10769/1.1
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