Wednesday, January 18, 2012

Highest Cited WRR papers ever

I had from WRR editor, Prof. Praveen Kumar the list of highest cited Water Resources Research Papers, one of the best  Journals in the Hydrological field. I asked to have this ranking in order to have another way to select and and papers to my collection of historic and benchmark papers for Hydrology.
I was not actually expecting an answer from Praveen but it cames (and I realized later that this record is easy to obtain having a WEB of SCIENCE and SCOPUS account) Results were stored in a file that you can retrieve here.

Being the most cited does not necessarily means being the best papers. Some very good papers could have been published very recently, and still not having enough citations to rank among the first ones. Some very good  papers could be too specialistic to be read by most of us fluency.  Besides some topic are of more broad interest than others, and this increase their citations' rates.  However, after all of these disclaimers, here there are the papers, some statistics, and comments. The paper grouped, for broad sub-fields, are about:


calibration and uncertainty  8
evapotranspiration and ecohydrology 6
experimental hydrology 2
geochemistry 5
geomorphology 22
groundwater 78
infiltration and vadose zone 29
other 10
precipitation 5
mathematical ans statistical 13
surface water 23

The dominance of groundwater papers is apparent, but this is probably a inheritance of the lated eighties and nineties. While browsing the recent papers there is more equilibrium between the fields covered.

Grouped for year of publication, the are distributed as shown below. 

The figures shows that they cover all the decades of publication of WRR from 1965 to 2003.

Grouped per decades these 201 paper are

1960 16
1970  36
1980  75
1990  68
2000  6 

So, the 20 higher cited papers are (the other can be seen in the xls file):

- MUALEM, Y, NEW MODEL FOR PREDICTING HYDRAULIC CONDUCTIVITY OF UNSATURATED POROUS-MEDIA, 1976, cit: 1818

- TOPP, GC, DAVIS, JL, ANNAN, AP, ELECTROMAGNETIC DETERMINATION OF SOIL-WATER CONTENT - MEASUREMENTS IN COAXIAL TRANSMISSION-LINES, 1980, cit: 1800

- BEVEN, K, GERMANN, P, MACROPORES AND WATER-FLOW IN SOILS, 1982, cit:1058

- CLAPP, RB, HORNBERGER, GM, EMPIRICAL EQUATIONS FOR SOME SOIL HYDRAULIC-PROPERTIES,1978, cit: 1034

- GELHAR, LW, AXNESS, CL, 3-DIMENSIONAL STOCHASTIC-ANALYSIS OF MACRODISPERSION IN AQUIFERS, 1983, cit: 986

- RITCHIE, JT, MODEL FOR PREDICTING EVAPORATION FROM A ROW CROP WITH INCOMPLETE COVER, 1972,cit: 931

- DUAN, QY, SOROOSHIAN, S, GUPTA, HV EFFECTIVE AND EFFICIENT GLOBAL OPTIMIZATION FOR CONCEPTUAL RAINFALL-RUNOFF MODELS, 1992, cit: 776

- SUDICKY, EA, A NATURAL GRADIENT EXPERIMENT ON SOLUTE TRANSPORT IN A SAND AQUIFER - SPATIAL VARIABILITY OF HYDRAULIC CONDUCTIVITY AND ITS ROLE IN THE DISPERSION PROCESS,1986, cit:645

- HIRSCH, RM, SLACK, JR, SMITH, RA, TECHNIQUES OF TREND ANALYSIS FOR MONTHLY WATER-QUALITY DATA, 1982, cit:577

- Legates,  GJ, McCabe, DR, Evaluating the use of goodness-of-fit measures in hydrologic and hydroclimatic model validation, 1999, cit:573

- CELIA, MA, BOULOUTAS, ET, ZARBA, RL, A GENERAL MASS-CONSERVATIVE NUMERICAL-SOLUTION FOR THE UNSATURATED FLOW EQUATION, 1990, cit:564

- GELHAR, LW, WELTY, C, REHFELDT, KR, A CRITICAL-REVIEW OF DATA ON FIELD-SCALE DISPERSION IN AQUIFERS, 1992, cit:554

- YEH, WWG, REVIEW OF PARAMETER-IDENTIFICATION PROCEDURES IN GROUNDWATER HYDROLOGY - THE INVERSE PROBLEM, 1986, cit: 546

- COSBY, BJ, HORNBERGER, GM, GALLOWAY, JN, WRIGHT, RF, MODELING THE EFFECTS OF ACID DEPOSITION - ASSESSMENT OF A LUMPED PARAMETER MODEL OF SOIL-WATER AND STREAMWATER CHEMISTRY, 1985, cit: 530

- FREEZE, RA, STOCHASTIC-CONCEPTUAL ANALYSIS OF ONE-DIMENSIONAL GROUNDWATER FLOW IN NONUNIFORM HOMOGENEOUS MEDIA, 1975, cit: 528

- JACKSON, RD, IDSO, SB, REGINATO, RJ, PINTER, PJ, CANOPY TEMPERATURE AS A CROP WATER-STRESS INDICATOR, 1981, cit:506

- Tarboton, A new method for the determination of flow directions and upslope areas in grid digital elevation models, DG, 1997, cit: 477

- CARSEL, RF, PARRISH, RS, DEVELOPING JOINT PROBABILITY-DISTRIBUTIONS OF SOIL-WATER RETENTION CHARACTERISTICS, 1988, cit: 467

- COSBY, BJ, HORNBERGER, GM, CLAPP, RB, GINN, TR, A STATISTICAL EXPLORATION OF THE RELATIONSHIPS OF SOIL-MOISTURE CHARACTERISTICS TO THE PHYSICAL-PROPERTIES OF SOILS, 1984, cit: 451
RICHARDSON, CW, STOCHASTIC SIMULATION OF DAILY PRECIPITATION, TEMPERATURE, AND SOLAR-RADIATION, 1981, cit: 440

Reading the list of these paper is apparent that the first ones belong to a interdisciplinary area of interest that cover hydrology, soil science, and, at least, agricolture.  The inverse modelling is also a pretty relevant topic, while surface hydrology is not present (except for Tarboton's paper, which however is on DEM treatment): which is a surprise to me!
The mean number of citations is around 300. So, a high cited paper, at least for WRR should have around 200 citations (unfortunately, my papers are still away from this).  A summary of the statistics is:

   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    
  184.0   208.0   241.0   302.9   318.0  1818.0    

The ten most recent papers among the most cited are:

- Houser, PR, Shuttleworth, WJ, Famiglietti, JS, Gupta, HV, Syed, KH, Goodrich, DC, Integration of soil moisture remote sensing and hydrologic modeling using data assimilation,  1998, cit: 185

- Legates, DR, McCabe, GJ, Evaluating the use of goodness-of-fit measures in hydrologic and hydroclimatic model validation,   1999, cit: 573

- Nepf, HM, Drag, turbulence, and diffusion in flow through emergent vegetation, 1999, cit: 239

- Western, AW, Grayson, RB, Bloschl, G, Willgoose, GR, McMahon, Observed spatial organization of soil moisture and its relation to terrain indices  TA 1999,  cit: 209

- Rodriguez-Iturbe, I, Ecohydrology: A hydrologic perspective of climate-soil-vegetation dynamics,   2000, cit: 213

- Iverson, RM, Landslide triggering by rain infiltration,  2000, cit:207

-McArthur, JM, Ravenscroft, P, Safiulla, S, Thirlwall,  MF, Arsenic in groundwater: Testing pollution mechanisms for sedimentary aquifers in Bangladesh  2001, cit:  279

-Zhang, L, Dawes, WR, Walker, GR, Response of mean annual evapotranspiration to vegetation changes at catchment scale,  2001, cit:  274

-Zhang, XB, Harvey, KD, Hogg, WD, Yuzyk, TR, Trends in Canadian streamflow, 2001, cit: 201

-  Vrugt, JA, Gupta, HV, Bouten, W, Sorooshian, S 2003, A Shuffled Complex Evolution Metropolis algorithm for optimization and uncertainty assessment of hydrologic model parameters

Neither between these appears a paper on surface waters. However, it is interesting to note that the topics covered are different from those of the highest cited papers. Meaning probably that each decade has its focus. 

Yearly citations rate show that the first group of papers are really outliers with respect to the others. However the mean number of citations per year is around 12, and if your papers has more that 5 citations per years, there is some hope that sometimes in the future it could enter in this rank.


 Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    
  4.244   7.960  10.420  12.300  14.190  56.250   


The ten papers with the highest annual average citations' rate are:

- TOPP, GC, DAVIS, JL, ANNAN, AP, ELECTROMAGNETIC DETERMINATION OF SOIL-WATER CONTENT - MEASUREMENTS IN COAXIAL TRANSMISSION-LINES,  1980, cit: 1800, citation rate: 56.25,

-  MUALEM, Y, NEW MODEL FOR PREDICTING HYDRAULIC CONDUCTIVITY OF UNSATURATED POROUS-MEDIA, 1976, citation rate: 50.5

- DR, McCabe, GJ, Evaluating the use of goodness-of-fit measures in hydrologic and hydroclimatic model validation Legates,  1999,cit: 1800,cit: , citation rate: 44.01

- DUAN, QY, SOROOSHIAN, S, GUPTA, V, EFFECTIVE AND EFFICIENT GLOBAL OPTIMIZATION FOR CONCEPTUAL RAINFALL-RUNOFF MODELS,  1992, cit: 776, citation rate:38.8

- BEVEN, K, GERMANN, P, MACROPORES AND WATER-FLOW IN SOILS,  1982, cit: 1058, citation rate: 35.3

- GELHAR, LW, AXNESS, CL , 3-DIMENSIONAL STOCHASTIC-ANALYSIS OF MACRODISPERSION IN AQUIFERS, 1983, cit: 986, citation rate: 34

- Tarboton, DG, A new method for the determination of flow directions and upslope areas in grid digital elevation models, 1997, cit: 477, citation rate: 30.4

- CLAPP, RB, HORNBERGER, GM, EMPIRICAL EQUATIONS FOR SOME SOIL HYDRAULIC-PROPERTIES, 1978 cit: 1034, citation rate: 24

- Gupta, HV, Sorooshian, S, Yapo, PO , Toward improved calibration of hydrologic models: Multiple and noncommensurable measures of information, 1998, cit. 402, citation rate: 23.3

- GELHAR, LW, WELTY, C, REHFELDT, KR, A CRITICAL-REVIEW OF DATA ON FIELD-SCALE DISPERSION IN AQUIFERS,  1992, cit: 554, citations rate: 19.2

Finally, the authors who wrote these papers are 337. Most of them appear once. Those who compare more than two times are: 


12           ABRIOLA, LM    3
12           BEVEN, K    3
12           CELIA, MA    3
12           COSBY, BJ    3
12           DAGAN, G    3
12           DIETRICH, WE    3
12           GORELICK, SM    3
12           GRAYSON, RB    3
12            IDSO, SB    3
12           KITANIDIS, PK    3
12           MCMAHON, TA    3
12           NIELSEN, DR    3
12           PAPADOPU.IS    3
12           SUDICKY, EA    3
12           VANGENUCHTEN, MT    3
12           WITHERSPOON, PA    3
12           WRIGHT, RF    3
7            FREEZE, RA    4
7            MANDELBROT, BB    4
7            RODRIGUEZ-ITURBE, I    4
7            SOROOSHIAN, S    4
3            GUPTA, HV    5
3            GUTJAHR, AL    5
3            HORNBERGER, GM    5
3            NEUMAN, SP    5
3            MONTGOMERY, DR    6
2            WALLIS, JR    6
1            GELHAR, LW   12

I must say that I know most of the Authors, many of them personally, since their work inspired mine, and just by googling their names it is clear that some of them gave some exceptional contribution even in other journals. So despite the many disclaimer citations say something. Someone of my hydrological heroes is missing: but doing benchmark papers is probably is slightly a different thing than writing a highly cited paper. 

Monday, January 16, 2012

Simulated effect of soil depth and bedrock topography on near-surface hydrologic response and shallow landslide triggering by Lanni, McDonnell, Hopp and Rigon


We have just submitted a paper  that, looked from a certain perspective, can be thought on the evolution of soil moisture content in presence of variable soil depth. In fact, variable soil depth, jointly with the fact that increases in hydraulic conductivity follows the increase in water pressure, and that hydraulic conductivity itself can often be considered negligible when the soil is unsaturated, delays the formation of a widespread water table in a hillslope. Therefore the effective contributing area above a point of a catchment is usually  not the total upstream area but just a part of it.  This obviously has consequences on the propagation of instabilities along a slope.



The Abstract of the paper:

This paper explores the effect of hillslope hydrological behavior on slope stability in the context of transient subsurface saturation development and landslide triggering. We perform a series of virtual experiments to address how subsurface topography affects the location and spatial pattern of slip surface development and pore pressure dynamics. We use a 3D Darcy-Richards equation solver (Hydrus 3-D) combined with a cellular automata slope stability model to simulate the spatial propagation of the destabilized area. Our results showed that the soil-bedrock interface and in particular, bedrock depressions, played a key role on pore pressure dynamics, acting as an impedance for the downslope drainage of perched water. Filling and spilling of depressions in the bedrock surface microtopography induced localized zones of increased pressure head such that the development of pore-pressure fields—not predictable by surface topography—lead to rapid landslide propagation. Our work suggests that landslide models should consider the subsurface topography in order to include a connectivity component in the mathematical description of hydrological processes operating at the hillslope scale. Quantitative soil- landscape methods combined with physically-based landslide models may improve our ability to predict shallow landslide potential. 

Among the original stuff presented in this paper, there is a tentativ to move away from the concept of instable points to the one of instable regions.  The traditional (simplified) approach based on the infinite slope stability (Ning Lu is discussing it here) is in fact used in modern GIS based program like SHALSTAB (here on ARCGIS or here on opensource GIS) or SINMAP to determine the instabilities of single points, which we try here to generalize a little. 

The paper draft is available here, if you are interested in. A related discussion can also be found in the previous papers by Lanni et Al., 2011 and in the draft by Cordano and Rigon, 2012.

Friday, January 13, 2012

Solving the Boussinesq's (groundwater) equation by Cordano and Rigon

Boussinesq's equation describes the motion of a free aquifer under the Dupuit hypothesis, or, if you prefer, the motion of the surface of  the water table. This paper just submitted for reviewing treats its numerical solution using a new method derived from previous work of Brugnano and Casulli (2008) and Casulli (2009). Let's talk the abstract:


This work presents with a new conservative finite-volume numerical solution for the two-dimensional groundwater flow (Boussinesq) equation, which can be used for investigations of hillslope subsurface flow processes and simulations of catchment hydrology. The Boussinesq Equation is integrated for each grid element and can take account of the local variability of topography and soil properties within the grid elements. The numerical method allows for wetting and drying of the water-table, which has been successfully simulated.
The stability and convergence of the method is shown to be guaranteed apriori by the properties of the solver itself. 
The numerics are validated against some approximate analytical solutions, and  compared to another numerical solver of the Boussinesq equation. Finally, the solver capabilities are further explored with simulations of the Panola experimental hillslope where  the bedrock topography, which is accurately known, causes complex wetting and drying patterns;  in this situation the importance of a two-dimensional description of subsurface flows to obtain properly simulated discharges becomes clear.


What is relevant in our paper, among other thing, is:

  • the cleanliness of the integration method (that makes the numerics fast)
  • the ability to deal with wetting and drying zones
  • the accurate  treatment of boundary conditions (which could, in theory, break the conditions of integrability a-priori)
The first appendix can be used as an introduction to the Newton's method for integration of non linear equations.

As usual, the code we provide is released with a GPL v3 license, and available for download, at the moment, in the GEOtop site. Emanuele Cordano wrote also some ancillary R code which plots the analytical solutions of the equation in some simplified setting described in the paper (under Packages - boussinesq in the CRAN site).

The model was used to create the reference conditions in the paper by Lanni et Al., 2011 [pdf]. The draft of the paper for curious can be downloaded from here. The final version can be retrieved through this post.

Monday, January 9, 2012

40 fascinating blogs on statistics


All the following is from:

http://www.bschool.com/blog/2011/40-fascinating-blogs-for-the-ultimate-statistics-geek/

There is no need of further comments:

At some point in nearly every (but not all) major and career path, statistics will be encountered. Even tangentially, they still define and describe everything from the efficacy of cancer medications to earned run averages, and everything in between. Understandably, the near-universality of the subject attracts scads of admirers, and the internet provides them with a lovely public platform to trade ideas and insights through blogs, forums, communities, podcasts and more. While not comprehensive, the following list offers up an eclectic mix of blogs to pique the interest of many different breeds of the statistics geek.

1- Probability and statistics blog
: Matt Asher finds statistics and probability everywhere, and his blog offers up some amazing, educational and provocative content.


2 -Xi'an's Og: Not all of the content presented here revolves around statistics, but this Universite Paris Dauphine professor sticks mainly with research, papers, events, computations and Bayesian subject matter.


3- Three-Toed Sloth: Math and statistics geeks wanting to see the disciplines applied to current events, science and plenty more will have plenty to love about Three-Toed Sloth.


4- Statisfaction: PhD students affiliated with the CREST research institute blog extensively about statistics, economics and plenty more relevant, often overlapping topics.


5- Freakonometrics: Anyone with a particular affinity for statistics as it relates to business, economics, finances and more seriously needs to give Arthur Charpentier's blog a visit. Those who do not speak French need only run it through Google Translate to read what he has to say.


6- R-bloggers: 140 contributors discuss the latest news and views from across the R community, which focuses on computational software for statisticians.


7- Statistical modeling, Causal Inference, and Social Science: From Dartmouth comes a frequently-updated, highly intelligent resource packed with discussions about statistics, art, political science and plenty of models.


8-The Endeavour: John D. Cook offers math, probability and statistics geeks plenty of intelligent commentary on a wonderful array of related subjects.


9- Revolutions: Give Revolution Analytics' blog a look for detailed discussions about their R programs, open source and — of course — statistics.


10- Numbers Rule Your World: Statistics are absolutely everywhere, and this blog peers into how they permeate daily life as well as marketing, business and economics.


11-The Numbers Guy: Many statistics buffs turn to this Wall Street Journal offering glimpses in how the media and the public use and abuse numbers every day.


12- Observational Epidemiology: Epidemiology, higher education and statistics collide in one frequently updated, insightful resource about the practical applications of the maths and sciences.


13 -Understanding Uncertainty: University of Cambridge's Statistical Lab and the Winton Programme it hosts hope to educate the public about the mathematical risks and uncertainties associated with numerous important topics and current events.


14 - Five Thirty Eight: Nate Silver with The New York Times blogs about the numbers that drive politics, with statistics and calculus forming the site's core.


15 -The Stats Blog: While this resource may not update as often as some of the others listed here, both The Stats Blog and its accompanying website deserve plenty of attention.


16 - Social Science Statistics Blog: Statistics fans who enjoy applying the associated formulas to psychology, sociology and other "soft" sciences would do well to follow Harvard's myriad takes on the matters at hand.


17 - Significance: As both a blog and a magazine, Significance brings statistics to the masses, making it a valuable resource for those new to the discipline.


18 - Realizations in Biostatistics: Check out this resource by a Bayesian biostatistician for some interesting, educational research on the numerical world of medicine and more.


19 - Blog about Stats: Everything readers need to know about this multi-author reference can be found right there in this title — it's a place where anyone who enjoys the subject can come and talk with like-minded individuals.


20 - R-statistics blog: It may update comparatively infrequently to some of the others, but readers curious about R and open source will still enjoy the content here.


21 - R-Chart: Take a look at R from the perspective of a web and database developer, who illustrates main points with some excellent, effective visuals.


22 - The Numbers: Gary Langer explains the statistical and mathematical findings behind recent polls and political undertakings.


23 - Lies, damned lies and statistics: Another seriously cool read merging daily life and statistics, this time focusing on social media, PR, branding and other topics of interest to businesspeople.


24 - Empirical Legal Studies: Several different writers dissect legal issues using statistical models and other empirical means in this enlightening resource.


25 - Stats Make Me Cry: In spite of its glacial schedule, Stats Make Me Cry is still worthwhile reading for those who enjoy learning as much as they can about the eponymous discipline.


26 - CoolData blog: Kevin MacDonnell researches and data mines in order to find interesting tidbits for anyone needing to raise funds for higher education. Statistics, naturally, finds its way into more than a few postings.


27 - Stats with Cats blog: Along with comforting pictures of feline friends, Charlie Kufs' accompaniment to his book makes statistics palatable for eager novices.


28 - LoveStats: For the statistician who embrace social media and market research, LoveStats delivers plenty to pique their interest.


29 - StatChat: Stay on top of news and views from around the worlds of applied statistics, data analysis and their intersections.


30 - Sabermetric Research: Baseball greatly appeals to plenty of statistics geeks out there, but visitors who prefer other sports still see some favorites represented here sometimes.


31 - Statistical Sage Blog: Four different writers keep a general statistics blog that plenty of students and professionals needing to collect data will find a valuable reference.


32 - Fishing in the Bay: Almost everything statistical eventually shows up here at Fishing in the Bay, which looks at things through an Antipodean lens.


33 - Blogs at AnalyticBridge: Scroll down to the "Blog Posts" section on the main page to read a broad number of perspectives from across the statistics and data analysis communities.


34 - Beyond the Box Score: For sabermetrics buffs, this highly engaging forum and blog delves deeply into the numbers that drive baseball.


35 - Mathematics & Statistics at Williams College: Another multi-author resource, offering statistics fans a chance to seek out different opinions and ideas regarding math, education, research and more.


36 - Mr. C's AP Statistics Blog: Visitors hoping to perhaps teach high school statistics someday may find this resource useful, though it does not update as often as some of the others on this list.


37 - dataists: Discover helpful methods the make gathering and analyzing statistical data as easy and painless as possible.


38 - FlowingData: Nathan Yau creatively blends the technical with the creative in his innovative visuals incorporating various statistical findings.


39 - Byte Mining: A statistician-turned-computer scientist talks about both his fields, along with the expected intersections and overlaps.


40 -information aesthetics: Another seriously cool blog blending statistics and data analysis with the latest trends in graphic design and art.

Thursday, January 5, 2012

Embargoes on the web

Paolo Tarolli sent to me the following link where the Nature Geosciences (and Nature indeed) ask for an embargo on information about unpublished papers. They argue among other things:

" it may well be in our authors' interest to limit pre-publicity of their results "

Frankly, I disagree on the statement (Well they can require what they want for their journal).

I am contrary to any embargo. I noticed that in Physics the free distribution of Preprints was massive even before the present era of web 2.0 with no problems whatsoever. At the same time, I believe (actually Nature would probably agree with me on this point) that I am able to judge my Science's topics with the same deepness of any other of my peers, and  that getting any scientific information early  is very useful and propel the advancement of science. 
Granted this, it would be very difficult in the present times, to filter out any written information, from the public. 

Moreover, if scientists do not make the effort to show and make to understand the public how science work, how can we believe it will support us ?  If we do not give to the society a sample of what the scientific debate is, and what is about ... in the matter, how can we think our work will not be degraded to opinons ? If we do not grow people to understand the problematics of our activities, and the methods to solve them, how can we believe science can be adopted  as a better way of thinking, and not just because it provides products ? 

On the contrary I appreciate the EGU open access journals where the policy to show discussion papers, both improve the "preprints", and make more careful most of the peer reviews.

Wittgenstein teaches: what can be said at all can be said clearly, and what we cannot talk about we must pass over in silence.

Tuesday, January 3, 2012

Flood Observatory at University of Colorado, Boulder



The information comes directly from their site, and data were obtained mostly by using remote sensing data from MODIS. In fact, The Flood Observatory uses orbital remote sensing to detect, measure, and map surface water changes. It includes:





1- River Watch, an experimental satellite-based river discharge measurement system (example).

2 - The Surface Water Record, a comprehensive map record of the Earth's changing surface water.

3 - Active Archive of Large Floods, 1985 to present (listing and characterization of large flood events).




4 - Rapid Response Inundation Maps, for individual flood events.

A library of Georeferenced photos from the field

They can be found at http://www.eomf.ou.edu/photos/. Pictures are usually pretty boring at the moment. But the idea is interesting and possibly the database will improve. An idea to follow.


Clicking on the photo you should be able to get the data connected to it.  The information come from EOS the AGU weekly journal, and the relative article is here.