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Investigation:

CD-01 (Denning / Dias)

LBA Dataset ID:

LBA-ECO_CD01_BRAMS

Originator(s):

1. LU, L.
2. DENNING, A.S.
3. DA SILVA-DIAS, M.A.
      4. SILVA-DIAS, P.
5. FREITAS, S.R.
6. SAATCHI, S.S.

Point(s) of Contact:

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

Dataset Abstract:

This data set consists of a single NetCDF file containing simulated three dimensional winds and CO2 concentrations centered on the Tapajos National Forest in Brazil in August 2001. Winds (u, v, and w components) and CO2 concentrations were generated at 31 vertical levels at 1 km grid increment with the Brazilian version of Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS). The simulation ran from the 1st through the 15th of August 2001, which was concurrent with the Santarem Mesoscale Campaign. The data file is in NetCDF format. Mesoscale circulations and atmospheric CO2 variations were investigated over a heterogeneous landscape of forests, pastures, and large rivers during the Santarem Mesoscale Campaign (SMC) of August 2001 (Silva Dias et al., 2004). The atmospheric CO2 concentration variations were simulated using the Colorado State University Regional Atmospheric Modeling System with four nested grids that included a 1-km finest grid centered on the Tapajos National Forest. Surface CO2 fluxes were prescribed using idealized diurnal cycles over forest and pasture that derived from flux tower observations; while surface water CO2 efflux was prescribed using a value suggested by in situ measurements in the Amazon region (Lu et al., 2005). Simulation ran from 1 August through 15 August 2001, which was concurrent with the SMC. Evaluation against flux tower observations and Belterra meteorological tower measurements showed that the model captured the observed 2-m temperatures and 10-m winds reasonably well. At 57 m the model reproduced the daytime CO2 concentration better than the nighttime concentration but missed the observed early morning CO2 maxima, in part because of the difficulties of simulating stable nocturnal boundary conditions and subgrid-scale intra-canopy processes. The results also suggested that the topography, the differences in roughness length between water and land, the T shape juxtaposition of Amazon and Tapajos Rivers, and the resulting horizontal and vertical wind shears all facilitated the generation of local mesoscale circulations. Possible mechanisms producing a low-level convergence (LLC) line near the east bank of the Tapajos River were explored. Under strong trade wind conditions, mechanical forcing is more important than thermal forcing in LLC formation. Persistent clouds near the east side of the Tapajos River may have a significant impact on observed ecosystem carbon flux and should be taken into account if tower fluxes are to be generalized to a larger region.

Beginning Date:

2001-08-01

Ending Date:

2001-08-16

Metadata Last Updated on:

2009-01-16

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 CD-01 Simulated Atmospheric Circulation, CO2 Variation, Tapajos: August 2001 :  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=907

Documentation/Other Supporting Documents:

LBA-ECO CD-01 Simulated Atmospheric Circulation, CO2 Variation, Tapajos: August 2001 :  http://daac.ornl.gov/LBA/guides/CD01_BRAMS.html

Citation Information - Other Details:

Lu, L., A.S. Denning, M.A. da Silva-Dias, P. Silva-Dias, M.Longo, S.R. Freitas, S.Saatchi. 2008. LBA-ECO CD-01 Simulated Atmospheric Circulation, CO2 Variation, Tapajos: August 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. doi:10.3334/ORNLDAAC/907

Keywords - Theme:

Parameter Topic Term Source Sensor
CARBON DIOXIDE ATMOSPHERE ATMOSPHERIC CHEMISTRY/CARBON AND HYDROCARBON COMPOUNDS COMPUTER MODEL ANALYSIS
SURFACE WINDS ATMOSPHERE ATMOSPHERIC WINDS COMPUTER MODEL ANALYSIS
UPPER LEVEL WINDS ATMOSPHERE ATMOSPHERIC WINDS COMPUTER MODEL ANALYSIS

Uncontrolled Theme Keyword(s):  ATMOSPHERIC CO2 VARIATIONS, CO2 CONCENTRATION, MESOSCALE CIRCULATIONS, RAMS, RAMS MODEL OUTPUT, TAPAJOS RIVER, THREE DIMENSIONAL WINDS, WIND

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
  PARA WESTERN (SANTAREM) -2.20400 -3.06900 -54.55800 -55.42400

Related Publication(s):

Lu, L.X., A.S. Denning, M.A. Silva-Dias, P. Silva-Dias, M. Longo, S.R. Freitas, and S. Saatchi. 2005. Mesoscale circulations and atmospheric CO2 variations in the Tapajos Region, Para, Brazil. Journal of Geophysical Research-Atmospheres 110(D21):102, doi:10.1029/2004JD005757.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Model outputs are provided in a single netCDF format data file, Tapajos_winds_CO2.nc with the following dimensions: time(360- ,level (31), x (97) and y (97).



*



Hourly model output beginning at 01-August-2001 and ending 15-August-2001.

*



1 kilometer grid increment.

*



The pole point for the oblique polar stereographic projection for each grid is -2.8 deg latitude, -55.0 deg longitude.

*



31 vertical levels (meters):



57.3, 188.7, 346.5, 535.8, 762.9, 1035.5, 1362.6, 1755.1, 2226.1, 2791.4, 3469.6, 4287.3, 5242.5, 6249.7, 7250., 8250., 9250., 10250., 11250., 12250., 13250., 14250., 15250., 16250., 17250., 18250., 19250., 20250., 21250., 22250., 23250.



Output variables: u, v, and w wind components and CO2 concentration.



*



u = zonal velocity component (m/s), range in this data set: -34.36687 to 21.89755



> Positive zonal velocities are from the west, negative zonal velocities are from the east.





*



v = meridional velocity component (m/s), range in this data set: -12.68975 to 16.59277



> Positive meridional velocities are from the south and negative meridional velocities are from the north.





*



w = vertical velocity component (m/s), range in this data set: -3.563875 to 12.91778







*



co2_t3 = CO2 concentration (ppm), range in this data set: 342.8621 to 407.8740





Data Application and Derivation:

Evaluation of mesoscale circulations, interpreting flux tower measurements, regional upscaling.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

Users of this model output should keep in mind that surface fluxes of CO2 were prescribed in the model using idealized diurnal cycles over forest and pasture vegetation derived from flux tower observations, and over surface water using a value suggested by in situ measurements in the Amazon region. The exact methodology of prescribing the surface fluxes as well as model comparisons to observations are described in Lu et al. (2005).

Process Description:

Data Acquisition Materials and Methods:

Three dimensional winds and variations of atmospheric CO2 concentration were simulated using the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) with four nested grids that included a 1-km finest grid centered on the Flona Tapajos. Surface fluxes of CO2 were prescribed in the model using idealized diurnal cycles over forest and pasture vegetation derived from flux tower observations, and over surface water using a value suggested by in situ measurements in the Amazon region. The distribution of vegetation types was derived from the 1-km International Geosphere-Biosphere Programme (IGBP) land-cover data set version 2.0 (Loveland et al., 2000). The simulation ran from the 1st through the 15th of August 2001, which was concurrent with the Santarem Mesoscale Campaign. Model configuration details, the methodology of prescribing the surface fluxes and model comparisons to observations are described in Lu et al., 2005.

References:

Loveland, T. R., B. C. Reed, J. F. Brown, D. O. Ohlen, J. Zhu, L. Yang, and J. Merchant (2000), Development of a Global Land Cover Characteristics Database and IGBP DISCover from 1-km AVHRR data, Int. J. Remote Sens., 21(6/7), 1303-1330.



Lu, L., A.S. Denning, M.A. da Silva-Dias, P. Silva-Dias, M. Longo, S.R. Freitas, S. Saatchi. 2005. Mesoscale circulation and atmospheric CO2 variation in the Tapajos Region, Para, Brazil. Journal of Geophysical Research-Atmospheres, 110, D21:102, doi:10.1029/2004JD005757.



Silva Dias, M. A. F., P. L. Silva Dias, M. Longo, D. R. Fitzjarrald, and A. S. Denning (2004), River breeze circulation in eastern Amazon: Observations and modeling results, Theor. Appl. Climatol., 78(1-3), 111-121.

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