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Description

The SPURS-2 raindrop ODM-470 disdrometer dataset was collected from the ship during both the 2016 and 2017 cruises. Please see file global attributes and Klepp et al. (2015, 2018) for information on the disdrometer: http://dx.doi.org/10.1016/j.atmosres.2014.12.014, https://doi.org/10.1038/sdata.2018.122 . As explained in the references and global attributes, small drops that cause voltage drops < 0.12 V (i.e. drops with diameters < 0.44 mm) cannot be distinguished from noise by this instrument, and are thus missed. This undercounting of small drops cannot be corrected, and prevents accurate estimation of DSD parameters such as Nw, D0, Dm with any confidence or precision since the minimum detectable drop size is close to the median drop size of tropical oceanic rain (Thompson et al. 2015, https://doi.org/10.1175/JAS-D-14-0206.1). Nonetheless, this dataset provides estimates of drop counts as a function of drop size for the remaining rain drops > 0.44 mm in diameter, and their associated rain rates and liquid water contents. The SPURS (Salinity Processes in the Upper Ocean Regional Study) project is a NASA-funded oceanographic process study and associated field program that aims to elucidate key mechanisms responsible for near-surface salinity variations in the oceans.

Product Summary

Platforms
Ships
Instruments
RADAR
Spatial Extent

N: 24.204 S: 5.055 E: -119.886 W: -144.783

Spatial Resolution
1 Meters x 1 Meters
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2016-08-11 to 2017-11-17
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2781747781-POCLOUD
Data State
COMPLETE
Number of Files/Granules
1
Processing Level
2
Published
Updated
Science Keywords
RAIN

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Thompson, E. J., Chen, H., & Drushka, K. (2023). SPURS-2 Disdrometer data [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/SPUR2-DISDR Date Accessed: 2026-04-18

Documents

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
bin_nums 128 size bins total, which are logarithmically spaced counts double -9999 1 to 128 1 N/A
D diameter associated with bin centerpoint mm double -9999 0.037504573686633 to 22.28379943779 1 N/A
dD bin widths mm double -9999 0.025728108695312 to 0.5634214718017 1 N/A
Dmax max drop diameter mm double -9999 0.39203320338447 to 21.720377965988 1 N/A
Dmax_i max drop diameter bin number 1 double -9999 13 to 127 1 N/A
edges bin edges mm double -9999 0.024640519338977 to 22.56551017369 1 N/A
mass mass per bin kg double -9999 2.7621758378491E-11 to 0.0057938379661618 1 N/A
nd n of D drop concentration meaning count per size bin m^-3 double -9999 0 to 1460.853813846 1 N/A
Nd N of D drop density meaning count per size bin per volume mm^-1 m^-3 double -9999 0 to 42837.675649436 1 N/A
ndrops drop count in each bin drop count in each bin double -9999 0 to 680 1 N/A
nsumdrops drop count in all bins drop count in all bins double -9999 0 to 3093 1 N/A
P rain rate mm hr^-1 double -9999 0 to 122.62622653744 1 N/A
Pd rain rate per bin mm hr^-1 double -9999 0 to 121.68962713147 1 N/A
Pfortran this is less trustworthy, we do not recommend using it mm hr^-1 double -9999 0 to 72.66 1 N/A
time time seconds since 2016-01-01T00:00:00Z double N/A N/A 1 N/A
urel_anem relative wind speed at disdro from cup anemometer m s^-1 double -9999 0 to 28.38 1 N/A
vfall fall speed per bin m s^-1 double -9999 -0.42081010661571 to 9.6499839232394 1 N/A
voltage voltage volts double -9999 0 to 5.24 1 N/A
W liquid water content g m^-3 double -9999 0 to 3.5474789938037 1 N/A
Wd liquid water content per bin g m^-3 double -9999 0 to 3.5028759760377 1 N/A
z radar reflectvity factor linear mm^6 m^-3 double -9999 0 to 68555034.869036 1 N/A
Z radar reflectivity factor logarithmic dBZ double -9999 -40 to 78.3603935607 1 N/A
zd radar reflectvity factor linear per bin mm^6 m^-3 double -9999 0 to 68553285.467457 1 N/A
Zd radar reflectivity factor logarithmic per bin dBZ double -9999 -40 to 78.36028273512 1 N/A
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