A Fractal Analysis of Rainfall Time Series

Fractal Rainfall

"Two-year series of 1-min rainfall intensities observed by rain gages at six different points are analyzed to obtain information about the fractal behavior of the rainfall distribution in time. First, the rainfall time series are investigated using a monodimensional fractal approach (simple scaling) by calculating the box and correlation dimensions, respectively. The results indicate scaling but with different dimensions for different time aggregation periods. The time periods where changes in dimension occur can be related to average rainfall event durations and average dry period lengths. Also, the dimension is shown to be a decreasing function of the rainfall intensity level. This suggests a multidimensional fractal behavior (multiscaling), and to test this hypothesis, the probability distribution/multiple scaling method was applied to the time series. The results confirm that the investigated rainfall time series display a multidimensional fractal behavior, at least within a significant part of the studied timescales, which indicates that the rainfall process can be described by a multiplicative cascade process."

The above comes from a study done by Jonas Olsson, Janusz Niemczynowicz and Ronny Berndtsson. with the Department of Water Resources Engineering, Lund Institute of Technology, Lund University, Lund, Sweden.  It was reported on in the WaterSISWEB site just as above - nothing else.

Can anyone tell me what this means and why it might be important?  John Fleck?  Is this up your alley?   I understand that fractals are patterns that exist at various scales so I'm guessing this report is saying that rainfall patterns are similar over various scales... of time?  Distance?  Intensities?

When I first read it I was sure it was an attempt by the Three Swedes to prove the 23 Enigma!  But I think now it's more sophisticated than that.  Now I'm thinking it's design is to expose the 6 degrees of separation from any of the 23 enigmas!  A mind-bender any way you look at it.

Water Data as Art? Perhaps.

"Drawing Water"

David Wicks turns environmental data into art through computer software that he creates.  One of his latest projects has to do with rainfall data and is shown as this post's visual.  (Click to enlarge)  What looks like a cool rendering of the United States, is actually 2011 winter rainfall data by location, tweaked, and placed in reference to regional water consumption by cities. In other words, this is a visual rendering of the relationship of where water falls in the US to where it is used.  The numbers that make up the rendering are rainfall data from the NOAA/NWS and water consumption data from the USGS.  

In his own words.. "The final placement and color of each line are determined by the influence of urban water consumers. The more water a city uses, the stronger its pull on the rainfall. As rainfall is pulled farther from where it fell, it becomes desaturated, turning from blue to black in print and to white in the projected installation."   For more detail on the data and/or the process click here.

My personal take on the artwork is one of trending more toward the abstract.  I don't see the water use relationships that I think were intended to be seen.  I can only surmise that Colby, Kansas doesn't show up because either we don't use much rainfall in the winter, or, we use exclusively groundwater.  It does appear that most of our rainfall heads somewhere East of St. Louis, though.  (I'm only kidding - I never expected to see Colby's influence!)

But actually, that's not all.  His program also includes an interactive component that allows a user to select a smaller portion of the US and to look at the last few days of precipitation, or one of several other preselected time periods.  This could be cool, but I still don't think I'm going to see Colby patterns that will result in an "aha" moment.  However, all said, I applaud Mr. Wicks' interest in the political nature of water and in attempting to portray this critical resource in a new and innovative way.  And I guess I'll mention it before anyone else does - it doesn't seem to me like California or Texas are getting their fair share.  Or am I looking at the picture backwards?

Anyone Watching the Feds Lately?

I have been monitoring the activity of elements of the very broadly cast Water Information Coordination Program (WICP) - originally established in the 1960's. With a simple memorandum in 1991 (Memorandum 92-01) OMB reconstituted this unit and updated its authority. Some of it's new objectives are:

To plan, design, and operate a cost effective national network for water-data collection and analysis that meets the priority water-information needs of the Federal government and, to the extent possible within available resources, the needs of the non-Federal community that are tied to national interests.

To coordinate funding, staffing, and the provision of other resources needed to support interagency water-information activities for ensuring the best use of available resources.

To collaborate, as appropriate, with other groups that are coordinating related categories of information, such as spatial data and meteorological information.

Great, all non-federal entities are to provide their data so that the feds can turn around and provide it back to them and others - only if there are available resources to do so and only if those uses are tied to national interests.  Sounds fair to me.  But wait, the effort gets better.

Within WICP, there has been formed an Advisory Committee on Water Information (ACWI) made up of federal, regional, state, local, industrial, academic and water-related association representatives who are to meet the objectives and requirements of Office of Management and Budget (OMB) Memorandum No. M-92-01 (directing ACWI to establish more effective working relationships and foster collaboration with State and local agencies, Indian Tribes, and the private sector) and to, again, provide advice and consultation toward a cost-effective national network of water-data collection and analysis that meets the priority water-information needs of the Federal Government and, to the extent possible within available resources, the needs of the non-Federal community that are tied to national interests.

ACWI is supposed to have members (not to exceed 35) made up of Federal agencies; Professional water-related associations; State and county water-related associations; Academia, Private industry; Water utility associations; Civil engineering societies; Watershed and land conservation associations; Ecological societies; Lake, coastal and ocean associations; and Environmental and educational groups. 

The actual member organizations of ACWI today are:  National Ocean Service (NOAA); National Weather Service (NOAA); Tennessee Valley Authority; US Army Corps of Engineers; NRCS (USDA); US Forest Service (USDA); Bureau of Land Mgt (DOI); Bureau of Reclamation (DOI); National Park Service (DOI); Office of Surface Mining (DOI); US Fish & Wildlife Service (DOI); USGS Water Resources (DOI); Office of Environmental Information (USEPA); Office of Water (USEPA); Assoc of State Geologists; Assoc of Metropolitan Water Agencies; Assoc of State Drinking Water Administrators; Assoc of State and Interstate Water Pollution Control Administrators; Interstate Council on Water Policy; National Assoc of Clean Water Agencies; National Assoc of County Planners; Western States Water Council; American Society of Civil Engineers; Electric Power Research Institute; National Council for Air and Stream Improvement, Inc.; Universities Council on Water Resources; American Water Resources Assoc; American Water Works Assoc; Ecological Society of America; Groundwater Protection Council; League of Women Voters; National Ground Water Assoc; North American Lake Management Society; and the Water Environment Federation.

This list comprises 14 Federal organizations; 8 Regional, state and local organizations; 3 Industry organizations; 1 academic organization; and 8 professional association organizations.  I guess this could work for a "federal first" product.

Within ACWI there are 8 subcommittees - Groundwater; Sustainability; Hydrology; Sedimentation; Monitoring; NAWQA Liason; Spatial Water Data; and Methods.  And within each subcommittee there are one or more work groups - the Groundwater subcommittee for example has 4 work groups.  Whew!

From where I sit, this looks like a massive federal effort to infuse most of the federal agencies into every nook and cranny and aspect of water data, policy and management.  I'd almost be receptive of a water data role for our federal brothers, but I get real nervous when they start talking about sustainable water management as a federal policy.  We'll keep watching.