Approach question

[Husam El Alqamy]

Dear List 

I have a question about the modelling approach I am adopting for climate change impact assessment for some species in UAE. I am using climatic and non climatic environmental variables in my models. and I am selecting the best performing combination of predictors through AIC score. so I try all combinations and select for the one with lowest AIC. The selected model may containg climatic and non climatic predictors. In order to project through time I replace those climatic predictors with their projected grids in the projection folder while the other non-climatic predictors are considered as constants and the resulting model is considered as the projected model and used for climate change impact assessment. 

Is this considered as good approach? Or should consider only the climatic predictors in my initial DSM and projections as to be a valid climate change projected model and ignore the other non-climatic predictors?

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Husam El Alqamy, B.Sc., M.Phil.
Sr. Biodiversity GIS Analyst ,
Environmental Information Sector, EIS
Environmental Agency Abu Dhabi,UAE
Antelope Specialist Group, ASG - IUCN

[Alaa Eldeen]

Dear Husam,

Regarding your question, i would agree with you in this approach which is consistent with this reference http://onlinelibrary.wiley.com/doi/10.1111/j.2041-210X.2011.00157.x/pdf.

Regarding the best combination approach I would comment on it.  here you apply AIC to compare among the models, but actually AIC is relying mainly on number of the parameters used in each model, and when you train your models with different variables of course the number of models' parameters will be not the same and the AIC will change accordingly. So, there is a need to find another measure to adopt the best combination among the all.

Cheers

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Alaa Eldin Soultan,  B.Sc, MSc.
Wildlife Conservationist,
St Katherine Protectorate,
National parks of Egypt,
Nature Conservation Sector,
Egyptian Environmental Affairs Agency, EEAA
Tel-Fax: + 2069- 3470033
Mobil:+201225773922



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