Major Step in Improving Forecasts of Weather Extremes Such as Floods and Droughts -

Moisture and heat fluctuations from the land surface to the atmosphere form a critical nexus between surface hydrology and atmospheric processes, especially those relevant to rainfall. While current theory has suggested that soil moisture has had a positive impact on precipitation, there have been very few large-scale observations of this. A team of researchers from Columbia Engineering, Geophysical Fluid Dynamics Laboratory, and Rutgers University has now demonstrated that evaporation from the land surface is able to modify summertime rainfall east of the Mississippi and in the monsoonal region in the southern U.S. and Mexico. One of their main findings is that evaporation from the land is, however, only able to modify the frequency of summertime rainfall, not its quantity.

read the full article here

I was wondering if this finding applies only for southern US or if it's also avalaible for Europe and others continents?
Anyway, this is a great progress in our understanding on how global climate works.

This study have to be compared with what we already know about global warming, especially in the US.
Back in 2007, another study, made by Bates and al. (Climate Change and Water, a Technical Paper of the Intergovernmental Panel on Climate Change, WG II (2007) concludes that:

* Observed warming over several decades has been linked to changes in the large-scale hydrological cycle.
* Climate model simulations for the 21st century are consistent in projecting precipitation increases in high latitudes (very likely) and parts of the tropics, and decreases in some subtropical and lower mid-latitude regions (likely).
* By the middle of the 21st century, annual average river runoff and water availability are projected to increase as a result of climate change at high latitudes and in some wet tropical areas, and decrease over some dry regions at mid-latitudes and in the dry tropics.
* Increased precipitation intensity and variability are projected to increase the risks of flooding and drought in many areas.
* Water supplies stored in glaciers and snow cover are projected to decline in the course of the century.
* Higher water temperatures and changes in extremes, including floods and droughts, are projected to affect water quality and exacerbate many forms of water pollution.
* Globally, the negative impacts of future climate change on freshwater systems are expected to outweigh the benefits (high confidence).
* Changes in water quantity and quality due to climate change are expected to affect food availability, stability, access and utilisation.

Observed water-related changes during the last century in the United States


Anticipated changes in the water cycle of the United States

Now, four years later, can we say that a real change is perceptible in US?
Here, in Europe, it's already a fact as there's no week without any droughts and "extreme weather" events news....

I'm glad you posted this because IMO weather forecasting - with all the modern technology - is actually worse now than it used to be.

Really, listen to your local forecasts, and then notice how many times they get it wrong even one or two days out when I seem to recall them being able to be be pretty accurate out a week or more in the past.

The "funniest" thing I've noticed is the radio people reading their printed forecasts in the morning - when you can look outside and see that they're already wrong!

They just need to set up a hotline to the weather modification programmes and they'll get their forecasts right.

Or wath Dutchsinse. He seems to be more accurate than the 'experts'.

reply to post by centurion1211

Exactly!!
Here, in West France were I live, it's even worse than that: when I listen to my local forecast, they talked about weather events that should occurs in a day or so, while it's already above our head!


reply to post by wcitizen

Sure!
Anyway, pardon my ignorance but what is "Dutchsinse"?