Jump to content
IMPORTANT ANNOUNCEMENT ABOUT LOGGING IN ×
  • WELCOME GUEST

    It looks as if you are viewing PalmTalk as an unregistered Guest.

    Please consider registering so as to take better advantage of our vast knowledge base and friendly community.  By registering you will gain access to many features - among them are our powerful Search feature, the ability to Private Message other Users, and be able to post and/or answer questions from all over the world. It is completely free, no “catches,” and you will have complete control over how you wish to use this site.

    PalmTalk is sponsored by the International Palm Society. - an organization dedicated to learning everything about and enjoying palm trees (and their companion plants) while conserving endangered palm species and habitat worldwide. Please take the time to know us all better and register.

    guest Renda04.jpg

Zone Confusion


Ed in Houston

Recommended Posts

I have seen many zone maps on the WWW. Many of them do not agree with one another. I suspect that much of the discrepancies between zone maps are due to the time periods that were used in the zone calculations.

Is there a standard for the number of years in zone calculations? If there is what logic was used to define that standard?

Many would agree that the climate is changing. Certainly if one chose to go back far enough in the zone calculations so that data would be included from the 1800s or even farther back into the little ice age, the zone maps would look quiet a bit different. When one wishes to make a planting they would probaly be more interested in their zone for the next 30 years instead of the past 30 years. This would work out fine if the climate models had a history of accurate predictions for future year average temperatures as then the zones maps could use those predictions to make a future zone map.

One of the more interesting zone maps I have seen is the interactive map that has been referenced a few times on PT and is given below.

http://planthardiness.ars.usda.gov/PHZMWeb/InteractiveMap.aspx

This zone map includes data from the years 1976-2005 so it includes the very cold late 1970s when it snowed in Miami and includes the cold spells of the 1980s decade.

It shows the downtown Houston average to be between 24F and 25F.

It shows the downtown Orlando average to be between 27F and 28F.

It shows Ellington Field in S.E Houston to have an average of about 23F.

I looked at the official data from Ellington field for the years 1990-2015 and it shows the average winter lows to be about 28F as opposed to the 23F for the period of 1976-2005 given in the interactive map.

From what I have seen posted on PT many believe that downtown Orlando has a 10a climate instead of a 9B climate as shown in the interactive map.

It must be clear at this point that the zone designations are highly dependant on the period of years included in the calculations which gets back to the question of what logic is used to determine the years used in zone map calculations. If we had highly predictive climate models future zone maps could be developed. But alas climatology is a soft science unlike the hard sciences like chemistry and physics.

Ed in Houston

Link to comment
Share on other sites

This is a topic that I will address when I get the time. Right now I am busy writing another chapter for my book and catching up on some school work.

Brevard County, Fl

Link to comment
Share on other sites

I am trying to develop a methodology that will approximate to calculating the warming effect in urban heat islands.

Brevard County, Fl

Link to comment
Share on other sites

I am trying to develop a methodology that will approximate to calculating the warming effect in urban heat islands.

Brevard County, Fl

Link to comment
Share on other sites

Interesting stuff... weather-warehouse was a very good link. Sacramento is listed Officially as Zone 9B but recently 10a in the following winters: 2014, 2010, 2008, 2007, 2005, 2004, 2003, 2002. (Majority of winters) I think the maps are okay, but they don't really take into consideration urban heating and other topology such as elevation and valley bottoms.

The suburban area where I am at is hilly and pretty dense. So I've got some urban heating and protection from the hills... yet the USDA temps are around the same as in the middle of the unpopulated valley areas 20 miles away.

Edited by enigma99
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Recently Browsing

    • No registered users viewing this page.
×
×
  • Create New...