15 votes
Accepted

Why does it rain more at night than during the day?

First off, your observation that Tamil Nadu gets more rainfall in the evening is partially backed by records. Sahany, Venugopal, and Nanjundiah, 2010 provide data on diurnal scale rainfall ...
kingledion's user avatar
  • 3,376
9 votes

Why is Egypt so dry?

If you take a look at the atmospheric circulation pattern, the Hadley Cells in particular, they tell the story. The northern edge of Africa is on the descending edge of a Hadley Cell, which means ...
justCal's user avatar
  • 1,186
8 votes
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Confusion with precipitation values in CORDEX MPI-ESM rcp data

TLDR; The precipitation values (and possibly some other variables; see below) need to be divided by 24. Background The global attributes of the netCDF file in the question provide an URL to a ...
daniel.heydebreck's user avatar
7 votes

Is there any place on Earth that is permanently a desert?

UserLTK, above, has mentioned the Dry Valleys of Antarctica and the Atacama desert as two notable examples of "permanent" deserts. It's likely that these two locations have been deserts for at lease ...
Knob Scratcher's user avatar
6 votes
Accepted

How much rain falls on the Earth each year?

That's a tricky question, it will vary from year to year but we can narrow it down with some assumptions so I can give an answer. The assumptions will be: All precipitation over the sea will become ...
Camilo Rada's user avatar
  • 17.7k
6 votes
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At what latitudes does the precipitation water for Europe evaporate?

A challenge is going to be "which moisture is from where". Because the atmosphere doesn't ever completely empty of moisture, for any given precipitation, which water molecules were from ...
JeopardyTempest's user avatar
5 votes

How to reconcile hourly vs. daily probability of precipitation in the forecast?

The hours are not independent of each other. For example, suppose there's a chance of a hurricane hitting the area. If it hits, it will be rainy every hour of the day. If it misses, it will not rain ...
Rich006's user avatar
  • 151
5 votes
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Where can I get historic hourly precipitation data for Italy?

The US NCDC has this link to surface hourly global data which I was indeed able to find Napoli on. It appears, based upon this page describing the World Data Center For Meteorology, that there may be ...
JeopardyTempest's user avatar
5 votes

How does temperature impact the elevation distribution of orographic precipitation?

Examining two extreme cases, one very cold and the other very warm, the amount of precipitable water in the very cold one will be far less than that in the very warm one. Even fully saturated, the ...
DavidH's user avatar
  • 348
5 votes

Can I interpolate rainfall data from stations outside of watershed for the watershed?

Yes, you can interpolate the rainfall from stations outside the watershed. However, the quality of the interpolation will depend on the distance between the stations and the watershed, the prevailing ...
haresfur's user avatar
  • 4,419
5 votes
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Easiest way to visualize precipitation drainage using raster elevation files in R?

It sounds like you're looking for flow accumulation (upstream) area, most likely. That's imperfect for what you're looking for (e.g. doesn't account for varying infiltration rates), but it's probably ...
damp_civil's user avatar
5 votes
Accepted

Drought in Scotland?

No there isn't a drought in Scotland, but there doesn't have to be for there to be a high fire risk. As you say, the west coast is often wet which means the conditions are ideal for the (slow) build ...
Mehmet Karatay's user avatar
5 votes
Accepted

Why hasn't all the water on earth evaporated and been frozen at the poles?

Frozen glacial ice flows downhill; even if the catchment (where the snow falls) never rises above freezing the ice there still flows towards oceans, ie does not stay where the snow fell. The edges of ...
Ken Fabian's user avatar
  • 2,121
4 votes

How does elevation affect the amount of rainfall received?

Elevation affects temperature which affects the amount of rain. Most raingauges around the world are within a few hundred metres of sea-level, i.e the range in which most people live. Within this ...
Gordon Stanger's user avatar
4 votes
Accepted

Digitalizing precipitation data from the image of weather map

You can convert the image to NetCDF data using gdal_translate. The command line looks something like: ...
Gemechu Fanta Garuma's user avatar
4 votes

What is the difference between Precipitable Water (PW or PWAT) and Quantitive Precipitation Forecast (QPF) in terms of computer weather model data?

Precipitable water is the total amount of moisture throughout the air (the total in the entire tropospheric air "column"; most moisture is found in the lowest few km, due to decreases in temperature ...
JeopardyTempest's user avatar
4 votes

Dissolved minerals

There are several processes that can cause a mineral to precipitate from solution. You mention one which is adding elements to the solution This could occur in a number of ways. For example, aragonite ...
haresfur's user avatar
  • 4,419
4 votes
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monthly temperatue by state

It may take a few minutes of work this way... But did find digging through NCDC's climate data inventory, the climatological rankings pages should help find what you're looking for if you're looking ...
JeopardyTempest's user avatar
4 votes

Can I interpolate rainfall data from stations outside of watershed for the watershed?

In short: Yes you can/should use stations outside of your watershed. More in detail: There is well known methods in hydrology to solve the situation you are presenting. One simple method is to ...
marsisalie's user avatar
  • 2,673
4 votes
Accepted

colder after snow

I think you're mixing two things together. There are generally 2 processes that correlate low temperatures during and after a snowfall, but they are separated. These are both based on physical laws ...
Droid's user avatar
  • 421
3 votes
Accepted

Need help understanding rain rate formulas from drop sizes

The first equation does not match up with the units. But first things first... What you're calculating when you calculate rain rate is an accumulation rate, which is volume flux through a plane (mass ...
ssorg's user avatar
  • 66
3 votes
Accepted

SPI (Standardized Precipitation Index) for 40 years seasonal mean

The SPI statistic can be considered a standard normally distributed random variable $SPI \sim N(0,1)$. Thus the expected value, or mean, of the SPI statistic is $0$, and its standard deviation and ...
kingledion's user avatar
  • 3,376
3 votes

How does elevation affect the amount of rainfall received?

Elevation affects precipitation significantly, especially in a mountain environment. On the windward side of a mountain, precipitation is increased. As air parcel rises due to increasing elevation on ...
zfjohnson's user avatar
3 votes

How do climatologists define the "start" of a rainy season in a unimodal monsoonal climate?

I find the following method very straightforward and elegant. So maybe I can convince you to consider it. For the South American (SA) monsoon, Silva et al. (2007) and Carvalho et al. (2012) proposed ...
ouranos's user avatar
  • 637
3 votes
Accepted

Is there a maximum size for a single snowflake?

According to Caltech physics professor Kenneth G. Libbrecht's site SnowCrystals.com This monster is, to my knowledge, the largest snow crystal ever photographed. It measures 10.1 mm (0.4 inches) ...
Keith McClary's user avatar
3 votes

Precipitation Totals past days online?

One of the best sites I know of for this type of analysis is the National Weather Service’s precipitation analysis site, which combines radar data, gauge observations, and satellite data to make an ...
Jonathan Thornton's user avatar
3 votes
Accepted

Circular rain cloud observed in rain radar

A way to check if those clouds and precipitation are real is to check the same area and time with another radar. This is the image loop of Sidney (Terrey Hills) radar for the same time (the same you ...
Pere's user avatar
  • 829
3 votes
Accepted

Is there a way to approximate the density of air during rain?

Air without rain has a mass of about $\ce{1200 g/m^3}$ at 20°C. You can figure out the amount of water in falling rain if you know the rate of accumulation (how much rain falls through a given volume ...
jeffB's user avatar
  • 798
3 votes

How to interpret precipitation probability?

It is likely that the forecast is made using an ensemble of runs from a weather model. As weather is chaotic (deterministic, but heavily dependent on initial conditions), each run will show a ...
Dikran Marsupial's user avatar

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