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Investigation:

LC-14 (Nepstad / Moutinho)

LBA Dataset ID:

LC14_RISQUE

Originator(s):

1. NEPSTAD, D.C.
2. LEFEBVRE, P.A.
3. SILVA, U.L.
4. TOMASELLA, J.
      5. SCHLESINGER, P.
6. SOLORZANO, L.
7. MOUTINHO, P.R.
8. RAY, D.

Point(s) of Contact:

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Dataset Abstract:

Severe drought in moist tropical forests provokes large carbon emissions by increasing forest flammability and tree mortality, and by suppressing tree growth. The frequency and severity of drought in the tropics may increase through stronger ENSO episodes, global warming, and rainfall inhibition by land use change. However, little is known about the spatial and temporal patterns of drought in moist tropical forests, and the complex relationships between patterns of drought and forest fire regimes, tree mortality, and productivity. A simple GIS soil water balance model, called RisQue (Risco de Queimadasa Fire Risk) for the Amazon basin was used to conduct an analysis of these patterns for 1996 through 2001. RisQue features a map of maximum plant-available soil water (PAWmax) developed using 1,565 soil texture profiles and empirical relationships between soil texture and critical soil water parameters. PAW is depleted by monthly evapotranspiration fields estimated using the Penman Monteith equation and satellite-derived radiation inputs and recharged by monthly rain fields estimated from 266 meteorological stations. Modeled PAW to 10 m depth (PAW10m) was similar to field measurements made in two Amazon forests. During the severe drought of 2001, PAW10m fell to below 25% of PAWmax in 31% of the region's forests and fell below 50% PAWmax in half of the forests. Field measurements and experimental forest fires indicate that soil moisture depletion below 25% PAWmax corresponds to a reduction in leaf area index of approximately 25%, increasing forest flammability. Hence, nearly one third of Amazon forests became susceptible to fire during the 2001 ENSO period. Field measurements also suggest that the ENSO drought of 2001 reduced carbon storage by approximately 0.19 Pg relative to years without severe soil moisture deficits. RisQue is sensitive to spin-up time, rooting depth, and errors in evapotranspiration estimates. Improvements in our ability to accurately model soil moisture content of Amazon forests will depend upon better understanding of forest rooting depths, which can extend to beyond 15 m. RisQue provides a tool for early detection of forest fire risk. Maximum Plant-Available water was calculated for the Brazilian Legal Amazon using tabular data on soil texture from Radam-Brasil soil sample pits, using a combination of pedotransfer functions from Tomasella and Hodnett, and Saxton. Water retention was then interpolated to 8km resolution, constrained by the Radam Brasil soils map polygons. The PAWmax map was later expanded to the Andean countries of the Amazon basin. Since soil texture information was not available for these areas, values from adjacent regions of similar soil types within Brazil were used assigned to polygons of the FAO soils map outside the Brazilian Amazon. Monthly precipitation (PPT) and evapotranspiration (ET) datasets were prepared by Javier Tomasella at INPE/CPTEC; data sources included rain gauge data available at CPTEC and from cooperative station data distributed by NOAA-WMO.

Beginning Date:

1995-01-01

Ending Date:

2001-12-31

Metadata Last Updated on:

2013-03-01

Data Status:

Archived

Access Constraints:

PUBLIC

Data Center URL:

http://daac.ornl.gov/

Distribution Contact(s):

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Access Instructions:

PUBLIC

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

LBA-ECO LC-14 Modeled Soil and Plant Water Balance, Amazon Basin, 1995-2001:  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1147

Documentation/Other Supporting Documents:

LBA-ECO LC-14 Modeled Soil and Plant Water Balance, Amazon Basin, 1995-2001:  http://daac.ornl.gov/LBA/guides/LC14_RisQue.html

Citation Information - Other Details:

Nepstad, D., P. Lefebvre, U.L. Silva Jr., J. Tomasella, P. Schlesinger, L. Solorzano, P. Moutinho, and D. Ray. 2013. LBA-ECO LC-14 Modeled Soil and Plant Water Balance, Amazon Basin, 1995-2001. Data set. Available on-line (http://daac.ornl.gov) from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A http://dx.doi.org/10.3334/ORNLDAAC/1147

Keywords - Theme:

Parameter Topic Term Source Sensor
EVAPOTRANSPIRATION ATMOSPHERE ATMOSPHERIC WATER VAPOR COMPUTER MODEL ANALYSIS
PLANT AVAILABLE WATER LAND SURFACE SOILS COMPUTER MODEL ANALYSIS
PRECIPITATION AMOUNT ATMOSPHERE PRECIPITATION COMPUTER MODEL ANALYSIS

Uncontrolled Theme Keyword(s):  DROUGHT, EVAPOTRANSPIRATION, FOREST(S), PLANT AVAILABLE WATER CAPACITY, PRECIPITATION

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
  LEGAL AMAZON BASIN 9.24000 -34.00000 -34.03500 -82.00000

Related Publication(s):

Nepstad, D., P. Lefebvre, U.L. Da Silva, J. Tomasella, P. Schlesinger, L. Solorzano, P. Moutinho, D. Ray, and J.G. Benito. 2004. Amazon drought and its implications for forest flammability and tree growth: a basin-wide analysis. Global Change Biology 10(5):704-717.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data are provided in tab-delimited ASCII format.




Data are organized in three directories:


PAW - Percent Available Water


PPT - Precipitation


ET - Evapotranspiration



File naming conventions:


Evapotranspiration</b>: etpi_mmyyyy.asc where mmyyyy ranges from 011006 to 102000, e.g.



etpi_011996.asc


...


etpi_102000.asc




Precipitation</b>: prec_mmyyyy.asc, where mmyyyy ranges from 011995 to 122001, e.g.



prec_011995.asc


....


prec_122001.asc






Percent Available Water</b>:


one file is available:


pawmax10m.asc

Data Application and Derivation:

These data can be used to evaluate flammability at the scale of the Amazon basin.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

Not available.

Process Description:

Data Acquisition Materials and Methods:

Not available.

References:

None cited.

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