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# Spatial variability and its scale dependency of observed and modeled soil moisture over different climate regions

## Details

**Authors** Li, B. and Rodell, M.

**Year** 2013

**Publisher** Hydrology and Earth System Sciences

**Kind of work** article

**Discipline** Hydrology

**Secondary disciplines** Climatology

**Applied** false

[Read it at the publisher](https://doi.org/10.5194/hess-17-1177-2013) 
10.5194/hess-17-1177-2013

## In authors' words

### What they set out to do (purpose)

To characterize the spatial statistics of soil moisture (mean, variability, skewness) across three U.S. climate regions and to examine how they depend on measurement scale.

### Who or what was studied (sample)

Three U.S. climate regions (dry, intermediate, wet) over a 198-day warm season, using in situ SCAN measurements, NLDAS Noah model estimates, and AMSR-E satellite retrievals.

### How they did it (methods)

Comparison of in situ, modeled and satellite soil moisture; spatial variability related to mean wetness, and to measurement support (footprint) and extent.

### What they found (results)

In situ means, variability and skewness differed among dry, intermediate and wet regions. Spatial variability peaked at intermediate mean soil moisture, which the authors attribute to the boundedness of soil moisture. Variability decreased from smaller to larger support and increased with extent, following a power law, with stronger scale dependency in larger-support data. Scale dependency varied by climate region, which the authors suggest relates to the scale dependency of precipitation variability. The model and satellite products had smaller dynamic ranges and showed the convex relationship only faintly or partly.

## Commentary

### In short

A study showing that soil moisture looks more or less variable depending on the footprint and extent of measurement, and on the climate region, and that models and satellites capture this differently from ground sensors.

### Response

The finding turns on Systems (variability changes with the size of the unit measured and the extent considered) and Perspectives (three measurement and modeling viewpoints give different statistics for the same field). Relationships enter in the link between soil moisture variability and precipitation variability. Caveats: the paper is empirical hydrology and does not frame its result as observer-dependence; the Perspectives reading is an interpretation of the contrast among instruments, and the Relationships claim is the authors' suggestion rather than a tested result. Based on results as summarized by the fetch tool, not the full text.

**Patterns it shows** S, R, P

Shows the structure is there

**Added** 2026-11-02

**How to cite this** Li, B. and Rodell, M. (2013). Spatial variability and its scale dependency of observed and modeled soil moisture over different climate regions. Hydrology and Earth System Sciences.