U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > Weather
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
 
Old 08-31-2019, 09:33 AM
 
80 posts, read 14,941 times
Reputation: 71

Advertisements

While making some fictional climates, I came across this dilemma: in the Koppen classification system, how is semiarid climate determined for cities very near to the equator, or that straddle the equator?

The calculation for cutoff precipitation for semiarid climates is based on how much precipitation falls in the "high sun" period. However, at the equator, there is no "high sun" period. And for cities that straddle the equator, do you follow the Northern Hemisphere or the Southern Hemisphere regime?

Take a fictional version of Quito for example. (https://en.wikipedia.org/wiki/Quito#Climate)

If this fictional Quito were exactly the same as real life, but it had about a quarter of its annual precip, would it be semiarid or not??? There is a distinct dry season in Quito, but is this during the high sun period? When is the high sun period in Quito? It would be impossible to classify it as semiarid (B-type climate) or non-semiarid (C-type climate).

What are your opinions? Thanks.
Reply With Quote Quick reply to this message

 
Old 08-31-2019, 10:01 AM
 
Location: Cork, Ireland
111 posts, read 15,265 times
Reputation: 60
You should just treat it as 30-70% in the high sun half, add 140 to your threshold.
Reply With Quote Quick reply to this message
 
Old 08-31-2019, 10:14 AM
 
Location: Seattle Area
795 posts, read 168,193 times
Reputation: 289
I think according to Koppen you just use April-September for the northern hemisphere and October-March for the southern hemisphere. However, this obviously isn't accurate. IMO this is one of the pitfalls of the Koppen system.
Reply With Quote Quick reply to this message
 
Old 08-31-2019, 02:34 PM
 
80 posts, read 14,941 times
Reputation: 71
Quote:
Originally Posted by QIDb602 View Post
I think according to Koppen you just use April-September for the northern hemisphere and October-March for the southern hemisphere. However, this obviously isn't accurate. IMO this is one of the pitfalls of the Koppen system.
True, but if there's a potentially semiarid city that straddles the equator (e.g. the location of Quito or Pontianak), you could argue North or South hemisphere. I guess this issue has never really popped up in real life so Koppen never really thought about it.
Reply With Quote Quick reply to this message
 
Old 08-31-2019, 10:43 PM
 
Location: Seattle Area
795 posts, read 168,193 times
Reputation: 289
Quote:
Originally Posted by micahdebrink View Post
True, but if there's a potentially semiarid city that straddles the equator (e.g. the location of Quito or Pontianak), you could argue North or South hemisphere. I guess this issue has never really popped up in real life so Koppen never really thought about it.
Technically it would then just depend on where the weather station is, as nonsensical as that sounds.
Reply With Quote Quick reply to this message
 
Old Yesterday, 12:13 AM
 
Location: Seattle
105 posts, read 30,371 times
Reputation: 63
I would either 1) go with whichever half of the year is cooler (even if only by a fraction of a degree), or 2) do what YoIronFistBro said; add 140 mm to the precipitation threshold as if there was minimal precipitation seasonality.
Reply With Quote Quick reply to this message
 
Old Today, 10:08 PM
 
Location: White House, TN
5,673 posts, read 3,997,409 times
Reputation: 3582
Personally, I'd just get rid of the semiarid classification altogether and create a new classification: "semiarid tropical" for those types of climates. But I'd use the 140 mm threshold for that for equatorial climates (within ~10 degrees of the equator)
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply

Quick Reply
Message:


Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Weather
Follow City-Data.com founder on our Forum or

All times are GMT -6.

© 2005-2019, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 - Top