© Crown copyright 2004 Page 1

Meteorological Inputs

Groundwater Workshop, BirminghamMurray Dale, 4/11/04

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Presentation Content

Rainfall Data

MORECS & MOSES

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Rain Gauge Network

Real time Daily - 200 Real time Hourly - 175 (1000 planned) Slow time Daily - 3500 Slow time hourly - 200

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Quality Control

QA team based in Edinburgh, lead by Ross Melville and Derek Ogle

Brochure availableConforms to British Standard BS7834 (1996) – Guide to the acquisition and management of meteorological precipitation data (establishing a network, user requirement, siting, data management, QA…)

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UK Radar Coverage

1 km coverage(50 km range)

2 km coverage(100 km range)

5 km coverage(250 km range)

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Rain gauge location(and 1km storm accumulation)

0 10 20 30 40 50 60 70 80 90 100 mm

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1km radar accuracy (1 of 3)

Woodford 5-minute rainfall data on 31/12/03, aggregated to 15-minute totals

0.00

0.50

1.00

1.50

2.00

2.50

21:00:00 21:15:00 21:30:00 21:45:00 22:00:00 22:15:00 22:30:00 22:45:00 23:00:00 23:15:00 23:30:00 23:45:00 00:00:00

Ra

infa

ll (

mm

)

raingauge

Hameldon Hill radar

Rainfall totals:Radar: 14.5mmRaingauge: 12.2mm

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1km radar accuracy (2 of 3)

Shawbury 5-minute rainfall data on 28/8/03, aggregated to 15-minute totals

0.00

0.20

0.40

0.60

0.80

1.00

1.20

07:3

008

:00

08:3

009

:00

09:3

010

:00

10:3

011

:00

11:3

012

:00

12:3

013

:00

13:3

014

:00

14:3

015

:00

15:3

016

:00

16:3

017

:00

17:3

018

:00

Rai

nfa

ll (m

m)

Raingauge

Clee Hill radar

Rainfall total:Radar: 12.1mmRaingauge: 12.6mm

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1km radar accuracy (3 of 3)

Dunkeswell 5-minute rainfall data on 1/12/03, aggregated to 15-minute totals

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

09:0

0:00

09:1

5:00

09:3

0:00

09:4

5:00

10:0

0:00

10:1

5:00

10:3

0:00

10:4

5:00

11:0

0:00

11:1

5:00

11:3

0:00

11:4

5:00

12:0

0:00

12:1

5:00

12:3

0:00

12:4

5:00

13:0

0:00

13:1

5:00

13:3

0:00

13:4

5:00

14:0

0:00

14:1

5:00

14:3

0:00

14:4

5:00

15:0

0:00

15:1

5:00

15:3

0:00

15:4

5:00

16:0

0:00

16:1

5:00

16:3

0:00

16:4

5:00

17:0

0:00

Rai

nfa

ll (m

m)

raingauge

Cobbacombe radar

Rainfall totals:Radar: 23.6mmRaingauge: 15.8mm

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Radar / Gauge data in Urban Drainage Modelling

RainObs.

...ay 2 f inal>Wet Day 2...ROD_NEC_Ev ent02

Rainf all

Depth (mm)

6.000

Peak (mm/hr)

6.000

Av erage(mm/hr)

0.744

Depth (m)

Min

0.2800.2190.232

Max

1.4360.5910.652

Flow (m3/s)

Min

0.0180.0210.028

Max

0.3550.2690.305

Volume (m3)

3831.9003361.2773943.132

Velocity (m/s)

Min

0.1500.3670.417

Max

1.5001.2461.403

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MORECS

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MOSES

Soil Moisture data derived from radar Advanced scientific representation of

processes 5km spatial resolution Hourly updated Provides information on soil moisture status

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MOSES

Soil moisture deficit from MOSES

Darcian flow of soil moisture

Deep drainage

Surface runoff

Evaporation frombare soil, trees,grass, crops,wet canopies etc.

Rain,Snow Radiation

Rootsextractwater

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Moses detail reference on-line

http://www.metoffice.gov.uk/research/nwp/publications/papers/technical_reports/fr.html

Report # 428

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MOSES-PDM – MORECS Inter-comparison

Project jointly funded by the EA and Met OfficeCompared two extreme hydrological events

Drought of 1975-76 and floods of 2000-01For 4 contrasting MORECS squares24 month periods investigated

Inter-comparison contrasted with findings from available literature

Study concluded that MOSES-PDM better represents processes of evaporation, drainage and soil moisture than MORECS

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A comparison of SMD for grass from MORECS, MOSES-PDM and observations at one site from 1995-1997. (Redrawn from Blyth

(2002))

0

20

40

60

80

100

120

140

160

Jan-9

5

Mar-9

5

May-

95

Jul-9

5

Sep-95

Nov-95

Jan-9

6

Mar-9

6

May-

96

Jul-9

6

Sep-96

Nov-96

Jan-9

7

Mar-9

7

May-

97

Jul-9

7

Sep-97

Nov-97

Date

SM

D (

mm

)

MORECS MOSES-PDM OBSERVATIONS

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Variable Difference from comparison

Period Support from literature review?

Possible causes

PE/AE MX>MS Winter MOSES canopy resistance, soil heat flux

Annual √

PE MX>MS Very dry summer MOSES canopy resistance

AE MX=0, MS>0 Very dry summer √ Fixed available water in MORECS, MOSES calculates water transfer in dry soil

EP MX>MS Autumn √ In MOSES the gradual wetting of the lowest soil layer gives a slower onset of drainage

EP MX<MS Summer, annual √ MOSES has less AE and also has

drainage when SMD>0

SMD MX>MS Spring √ MORECS has more AE

MOSES / MORECS Comparison Summary

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Inter-comparison

MORECS uses the science and concepts of the late 1970s; the update in 1995 introduced more realistic soils data, but did nothing to change the basic science. MOSES includes more recent developments in evaporation and soils modelling including: Canopy resistance to moisture transfer which interacts with

weather Soil heat flux modelling Soil moisture movement modelling, snowmelt, surface runoff 5 km soils and land use, but only 1 farm crop type PDM represents a range of soil properties to represent soil

moisture variability and runoffThis report has shown the benefits of these

improvements

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Summary

Raingauge network details, planned real-time gauge increase, QC obligations

Radar – more appropriate for spatial rainfall than point source data (gauges)

MORECS – 1970s model, modifications in 1990s

MOSES – higher resolution (time and space), better representation of reality