Naked Science Forum

Life Sciences => The Environment => Topic started by: DoctorBeaver on 30/01/2008 18:08:54

Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 30/01/2008 18:08:54: Is there anything to show that grass is indeed greener on 1 side of a hill as opposed to the other side?

The north west of the UK is far wetter than the eastern side due in no small part to the hills and mountains of the Penines and the Lake District causing precipitation. Is there any evidence to show that the western sides of these hills are lusher & more verdant than the eastern sides?
Title: Is the grass greener on the other side?
Post by: paul.fr on 02/02/2008 14:51:35: Are you thinking of orographic enhancement?

Basically, this describes the situation where more rain falls on one side (the windward side) of a mountain range than the other(leeward side).
Title: Is the grass greener on the other side?
Post by: another_someone on 02/02/2008 16:36:10: Quote from: DoctorBeaver on 30/01/2008 18:08:54
Is there any evidence to show that the western sides of these hills are lusher & more verdant than the eastern sides?

The Yorkshire moors (there are no Cumbrian moors)?
Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 02/02/2008 16:43:08: I know there are no Cumbrian moors.

I don't necessarily mean just the N Yorks Moors (in fact I believe the Dales are closer to the Pennines than the moors are). Anywhere north from, say, Derbyshire.
Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 02/02/2008 16:43:53: Quote from: paul.fr on 02/02/2008 14:51:35
Are you thinking of orographic enhancement?

Basically, this describes the situation where more rain falls on one side (the windward side) of a mountain range than the other(leeward side).

Basically, yes.
Title: Is the grass greener on the other side?
Post by: paul.fr on 11/02/2008 15:21:12: The things i do for the beaver! Does he appreciate it?...

Doc. Not knowing the answer, i contacted Professor Geraint Vaughan of the School of Earth, Atmospheric and Environmental Sciences University of Manchester, Manchester UK, I slightly changed your question to one about Orographic precipitation.
This is his reply:

I passed this on to a colleague who suggests:

Well it seems to me that it is a complex question (a good question) which depends upon a variety of factors, and there is no simple answer. Just a few of the factors are,

* The susceptibility of the region in question to foehn-type effects and the moisture content of the upwind flow
* Altitude of the mountains/hills in question
* Orientation of the mountains (are they South(ish)-facing?)
* The occurrence of severe winds and rotors also effects vegetation - vegetation tends to be "lower" in regions where these are prevalent (i.e. fewer trees)
* Occurrence of snow and effects due to snow accumulation

There are obviously feedbacks between all of these effects and quantifying/separating them would be quite difficult...there is undoubtedly a component of vegetation change which can be attributed to the presence of mountains, but the precise nature is quite complex. Just one example of which I am familiar, the Sierra Nevada mountain range and Owens Valley (which is downwind of the Sierras) in California. The Owens Valley is quite barren consisting of mostly brush; upwind is very lush with a diversity of flora and fauna. *However* the Owens Valley used to be quite lush in the 1920s - the city of LA diverted the rivers and streams to provide water for LA - thus effectively making a desert of the valley. This just to illustrate the complexity of the problem.

I am a bit busy today but I will look into it further tomorrow/in a couple of days. In the meantime your correspondent may wish to look at the following which all have relevant material:

Mountain Weather and Climate, R. G. Barry, Routledge 1992 (and other eds). See in particular pages 84ff and Fig. 2.3.5 which shows the change in vegetation for a mountain in Switzerland. This examines the survival of larch plantings upwind and downwind of the crest (the survival rate dramatically falls of downwind), also the change in vegetation over the mountain structure.

Also look at

Mountain Meteorology: Fundamentals and Applications by C. David Whiteman , OUP 200

Boundary Layer Climates, T. R. Oke, Routledge 1990 (and other eds)

Hope that helps!
Cheers,
Ralph
Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 11/02/2008 19:05:50: WOW! Thank you, Paul (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fbowing%2F2.gif&hash=bcb35f58b56db9f8918c773ad3ccccd7)
Title: Is the grass greener on the other side?
Post by: JimBob on 12/02/2008 03:35:36: Why didn't you ask about trees?
Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 12/02/2008 08:07:27: Quote from: JimBob on 12/02/2008 03:35:36
Why didn't you ask about trees?

He already knows his tree times table [:D]
Title: Is the grass greener on the other side?
Post by: paul.fr on 12/02/2008 08:26:20: The book The Daily Telegraph Book of The Weather (http://www.weatheronline.co.uk/reports/philip-eden/By-Philip-Eden.htm)by Philip Eden (http://www.rmets.org/about/people/council.php)does have a few pages about orographic enhancement, about 4 pages worth.
A nice bit of light reading.
Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 12/02/2008 08:29:27: Thanks, Paul. I'll try to find that.
Title: Is the grass greener on the other side?
Post by: paul.fr on 12/02/2008 08:48:44: Quote from: DoctorBeaver on 12/02/2008 08:29:27
Thanks, Paul. I'll try to find that.

Your library should have a copy. The part about orographic enhancement is on ...goes to book shelf...pages 8 through 11.
Title: Is the grass greener on the other side?
Post by: DoctorBeaver on 12/02/2008 08:54:58: (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fthumbs%2F3.gif&hash=02c7799e545a77dfc1a9dae2111f9745)
Title: Is the grass greener on the other side?
Post by: neilep on 13/02/2008 03:15:12: As a firm believer in empirical study I just went and looked over the fence into next doors garden.......I confirm that MY side is greener.....as he has a patio !......so........to corroborate my belief in empirical study...I climbed over the fence into his garden and looked over into my garden !!

Yes...yes...it is true !!

Glad I could help !