Please correct your site as I was going to use this article for my Yr8 maths class to reference, but I am unable to do so.
View more comments. We track the weather makers across Australia, the tropics and New Zealand as stormy weather heads to NZ itself over…. The next five days will likely see well over mm accumulate on the West Coast as a series of fronts…. A front pushes northwards over the South Island today then onto the North Island later this evening or overnight.
A desert is a region that receives less than 10 inches mm of rainfall per year on average per year. The average annual rainfall varies from mm at Tangiers and mm at Casablanca to mm at Essaouira and to mm in the Sahara.
Yes, medicine can be measured in milliliters, but it can also be measured in cubic centimeters, or cc, which are identical to milliliters. Volume is measured in ml. Weight is measured in grams. Any liquid can be measured in ml.
Mean annual rainfall is mm. Slovenia gets an average of mm of rainfall a year due to its closeness to the mountains and alps. Italy and Germany get about mm perception a year and United Kingdom gets about mm of rainfall. It varies. Koalas are found in areas of rainfall varying from about mm annually down to about mm annually. Milliliters are a measure of liquid volume. Bread is solid, and not measured in milliliters.
It depends on the period of time you are talking about. For an annual rainfall, mm would be considered arid. An area can have as much as mm of rain a year and be considered a desert. Annual rainfall varies from around mm in the north of the Sahel to around mm in the south.
That depends entirely on how heavy the precipitation is. Usually instead of individual drops, rainfall is measured in mm. Average Annual Rainfall for Hobart is about mm. Log in. Math and Arithmetic. Rain and Flooding. Study now. Using special computer programs, it is possible to convert the amount of energy received into the amount of rain. It is important to remember that a radar does not directly measure the amount of rain, but instead measures the amount of energy sent back by the drops.
This conversion of energy into the amount of rain turns out to be tricky and people are still doing research to improve it [ 3 ]. For example, currently the drop size distribution and drop location within a radar pixel are assumed homogeneous. It is an over simplification of the reality which can affect the measurements [ 4 ]. The computer program enables the radar equipment to estimate the amount of rainfall in places that are far away it. The radar equipment can spin around and can also change its angle, so that it can estimate the rain rate in its entire surroundings.
Depending on the type of radar, it is possible to estimate rainfall up to — km from the radar equipment. Numerous developed countries have a network of radar equipment. By combining the data collected by all of the different radar equipment, we can obtain maps of rainfall over the whole country.
Figure 3B shows an example of a rainfall radar map measured by radar equipment at Ecole des Ponts ParisTech. The variability of the rainfall can be seen—notice the two very intense cells on the lower part of the map, in yellow and red. Rainfall is extremely variable, both over time and between different locations, which makes it very difficult to measure.
A rain gauge basically collects water falling on it and records the change over time in the rainfall depth, which is usually expressed in mm. You can get much more detailed information with disdrometers. A drisdrometer generates a sheet of light that is partially blocked when a drop falls through it. To create rainfall maps that measure rainfall over multiple locations, we have to use radar, which basically sends some energy into the atmosphere and analyses the portion of that energy that is returned to it when it bounces off the rain drops in the atmosphere.
There are still a lot of scientists working ways to accurately measure rainfall over time and in multiple locations at once. The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Making rainfall features fun: scientific activities for teaching children aged 5—12 years. Earth Syst. Multifractal comparison of the outputs of two optical disdrometers. Radar for hydrology: unfulfilled promise or unrecognized potential? Water Resour. Share on Facebook. Core Concept Published: August 14, Divide that volume by the area of the top of the gauge and you get mm of rain.
Most country's weather services report the amount of rain over a day and add the amounts together to get monthly or annual measurements, but it is possible to take measurements more frequently.
More frequent measurements can be used to report rainfall intensity over a shorter period. So you, for example, could report the maximum hourly rainfall intensity within a day. You can also use more frequent measurements to calculate how quickly streamflow responds to a rainstorm. For the sake of the argument let's imagine a flat area with impermeable ground, like rock, and an impermeable wall around it.
After it has rained for some time with a certain intensity over that area — everywhere the same —, there will be a certain height of water on the ground, which will be the same height all over this flat area. This height is measured in millimeters and reported. You can now go and divide this area up in square meters, or soccer fields, or square milimeters; the height of the water would obviously not change.
That's the beauty of this measurement: It is independent of any particular area. These are unrealistically ideal assumptions. The intensity or duration differed from place to place, the ground is not level, water seeps away etc. So the statement actually says: "This station measured a rain event which would cover any area with x mm of rain if it had rained everywhere the same amount as it did here.
In your case, "last Friday", one may assume a 24 hour calendar day. It's also often not possible to make a reliable statement for a larger area, especially in the case of local severe weather events. One can make an estimation based on measurements from different stations in the area and qualitative observations, but the only reliable accurate statements which can be made are factual measurements at weather stations; everything else is inferred, as in your example about all of Hong Kong.
I can imagine though that among Meterologists the sentence "Hong Kong reports 3 mm of rain" is taken to mean "The Hong Kong Observatory reports 3 mm of rain", and equivalently for other places. Rainfall is measured with a rain gauge. This one goes up to 12 cm or mm, so 3 mm would just be a few drops at the bottom. As you can imagine, it doesn't matter how big this gauge is, as long as the sides are straight. A larger cylinder will hold more water, but it has a larger opening to collect rain, so the measured rainfall is the same in either case.
Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Learn more. What does a mm of rain mean? Ask Question. Asked 3 years, 4 months ago. Active 10 months ago. Viewed 86k times.
What is the time period? Is it measured per day, per hour, per minute? Improve this question. You need the precip rate for that. Show 10 more comments. Active Oldest Votes. Improve this answer. That's a measurement in units of inverse length.
0コメント