The data within the particular urban catchment would be helpful. However, it is difficult to mention that only urbanisation has an impact. most of the time it would be the impact of collective factors

Then, statistical analysis such as principle component would be helpful.

will you explain more in detail or give some reference where it have been done. means proved that the change in rainfall is due to urbanisation only, not on other factors.

Ok, let me

Some urban tracers could be included in the chemical analysis (i.e. Pb). The stable isotopes (at least 18O and D) can be very helpful for the precipitation balance and sources distinguishing on the urban area. In our case, we used pH, electrical conductivity and Pb, but it was for the snow and it is a little bit different. May be for the rain it can be a comparison between the baseline (if it is established) and urban area. Major ions: Cl, SO4 and Na can be a cheap tracer also for the comparison between precipitation in your study area and worldwide (or regional) atmospheric water composition. PCA and factor analysis would be helpful for a long term measurements.

Thanks for your answer. What you have done is for surface water quality. but do you have any reference of PCA or factor analysis done. It is a good idea to compare the water vapour as you suggested. but still how to prove it is only due to urbanization, not due to other factors

Yes, I am agree that it is not so easy to differentiate. Please find the attached paper (but it is on surface waters) about the urban tracer and there is a PCA also. May be it can be helpful.

Thank you Yuliya.

Dear Saha,

Long-term data from near meteorological station(s) can be taken and then the same periodic data from hydro-graphic station (outlet of watershed) are required.

Surely, many factors are effective; namely, urbanization, land cover changes, changes is rainfall distribution (spatio-temporal), and many others.

For them, you can investigate their changes through the time series, one- by-one, and compare them.

Using the GIS and RS techniques to investigate the urbanization changes are highly advisable. By the means, you can compare the changes in (rapid) urbanization and its effects on rainfall.

Regards,

Mohammad Imangholiloo

Dear Saha,

Due to rapid urbanization we are seeing Urban Heat Island Phenomenon which leads to heavy rainfall in urban areas and leads to urban flooding.As cities are expanding vegetation (green cover) is vanishing and the asphalt, concrete etc absorbs heat and added to that we have lot of gases pumped to the atmosphere by the industries

which tend to increase the temperature. Even in day to day life we feel this affect while going in our vehicles you may feel the heat in city are the moment we pass though outskirts of city we feel the cooling affect. Average temperatures in a city can be as much as six to eight degrees Fahrenheit higher than surrounding rural and suburban landscapes. This increased temperature causes the air over a city to be warmer than the air surrounding it. This air when rising meets cool air it precipitates causing heavy downpour in that region.

You may

1. See the landuse/landcover changes in your study area during the last one decade from satellite images.

2.Then compare the temperatures and rainfall and landuse relation.

Regards

CMBhatt

Thank you sir for your answer. Your answer cleared my doubt to some extent. Sir, do you have any reference of such type of study done for any indian cities. As i am not able to find one.

Hi Saha,

You probably find it interesting to read speical topic papers on climatic effect of urbanization in Advance in Climate Change Research. One of the paper is about urbanization effect on short-duration intense rainfall in the Pearl River basin.

You may also find a paper by Yang et al. (2012?) in International Journal of Climatology, which analyzed the urbanization effect on hourly precipitation in Beijing City.

Good luck.