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NMQ: National Mosaic and Multi-Sensor QPE

Comparisons of rainrates from gauges and NMQ over HalfDeg Gauge Network, MD-VA

Gauge data

A network of 14 indvidual gauge sites was deployed in an approximately 0.5-degree grid area over Delmarva Peninsula near Maryland-Virgina boundary. Three tipping-bucket gauges were equipped at each of Sites 01-09, and two at each of Sites 10-14. Here is a list of these gauge sites and their locations as well as their deployment dates.
    SiteID         Lat(N)        Lon(W)       Installation Date
    0001         38.03231      75.39695     Fri, 21 February 2014
    0002         38.33289      75.70567     Wed, 26 February 2014
    0003         38.19720      75.69918     Thu, 29 December 2011
    0004         38.16560      75.39945     Thu, 05 January 2012
    0005         37.93716      75.46634     Fri, 20 August 2004 (Gauges A&B),Gauge C was installed on Fri, 30 May 2008
    0006         37.92781      75.72054     Fri, 16 December 2011
    0007         38.01686      75.82676     Thu, 22 December 2011
    0008         38.34092      75.51331     Tue, 24 August 2004 (Gauges A&B),Gauge C was installen on Tue, 03 June 2008
    0009         38.19685      75.36974     Mon, 24 March 2014, In addition, NASA38 (A&B) was moved to Site09 on 06 May 2015. So, 5 gauges at Site09.
    0010         38.36982      75.65482     Wed, 04 Jun  2014 (NASA0012)
    0011         38.01403      75.52278     Mon, 21 July 2014 (NASA0019)
    0012         38.26268      75.34166     Thu, 21 Aug  2014 (NASA0025), moved from (37.93456  -75.47101) on 21 Aug 2014, then moved to Site0016 (38.05473, -75.40990) on 2015-Apr-14
    0013         38.33173      75.40291     Thu, 16 Oct  2014 (NASA0022)
    0014         38.12071      75.73399     Thu, 05 Feb  2015 (NASA0005)
    0015	     38.012383     75.455125    Mon, 09 Mar  2015 (NASA0017)
    0016	     38.054728     75.409900    Tue, 14 Apr  2015 (NASA0025)
    0017	     38.36986      75.31886     Mon, 08 Jun  2015 (NASA0006)
    

All these gauges measure rainfall in increments of 0.01 inch (0.254 mm).

A/B/C gauges Comparisons

Comparisons with NMQ at various scales

The following figure shows the areal map of HalfDegGrid Gauge Networks along with 0.1o grids. The dots denote locations of the individual gauge sites with their identification numbers indicated on the right.

The gauge tip data are averaged over the entire network, and compared with the average NMQ rainrates over the area [75.9W->75.3W, 37.9N->38.4N] at hourly, 3-hourly and daily resolutions.

Since most gauges started to report rain tips from Mar 2014, both the NMQ and gauge data from Mar 2014 are included in following comparisons. Following plots are updated to Dec 31, 2015. Note large amount of gauge data after Aug 2015 are not available yet as of this posting on 24 Mar 2016.

  • Cumulative rainfall

  • Scatter plot

  • Mean difference and relative error

  • PDF by occurrence and volume
    In the PDF plot, rainrate thresholds are set to 0.1, 0.2 and 0.5 mm/h.

    The inserted "Agreement" in the PDF plot is defined as the fraction of both NMQ and gauge report the same rain category: rain ( rainrate >threshold), no rain (rainrate <=threshold) among all available observations.

    Agreement=N[(r>T & g>T) + (r<=T & g<=T)] / N(r>=T & g>=T)
    where T is rain threshold (0.1,0.2 0r 0.5 mm/h), N is sample size, r is NMQ rainrate, and g is gauge rainrate. Be definition, Agreement is between 0 (worst) and 1 (best).



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