Identification

Title

Historic Standardised Precipitation Index time series for IHU Hydrometric Areas (1862-2015)

Abstract

Standardised Precipitation Index (SPI) data for Integrated Hydrological Units (IHU) Hydrometric Areas (Kral et al. [1]). SPI is a drought index based on the probability of precipitation for a given accumulation period as defined by McKee et al. [2]. SPI is calculated for different accumulation periods: 1, 3, 6, 12, 18, 24 months. Each of these is in turn calculated for each of the twelve calendar months. Note that values in monthly (and for longer accumulation periods also annual) time series of the data therefore are likely to be autocorrelated. The standard period which was used to fit the gamma distribution is 1961-2010. The dataset covers the period from 1862 to 2015. NOTE: the difference between this dataset with the previously published dataset 'Standardised Precipitation Index time series for IHU hydrometric areas (1961-2012)' [SPI_IHU_HA] (Tanguy et al., 2015 [3]), apart from the temporal extent, is the underlying rainfall data from which SPI was calculated. In the previously published dataset, CEH-GEAR (Keller et al., 2015 [4], Tanguy et al., 2014 [5]) was used, whereas in this new version, Met Office 5km rainfall grids were used (see supporting documentation for more details). Within Historic Droughts project (grant number: NE/L01016X/1), the Met Office has digitised historic rainfall and temperature data to produce high quality historic rainfall and temperature grids, which motivated the change in the underlying data to calculate SPI. The methodology to calculate SPI is the same in the two datasets. [1] Kral, F., Fry, M., Dixon, H. (2015). Integrated Hydrological Units of the United Kingdom: Hydrometric Areas without Coastline. NERC-Environmental Information Data Centre doi:10.5285/3a4e94fc-4c68-47eb-a217-adee2a6b02b3 [2] McKee, T. B., Doesken, N. J., Kleist, J. (1993). The Relationship of Drought Frequency and Duration to Time Scales. Eighth Conference on Applied Climatology, 17-22 January 1993, Anaheim, California. [3] Tanguy, M.; Kral., F.; Fry, M.; Svensson, C.; Hannaford, J. (2015). Standardised Precipitation Index time series for Integrated Hydrological Units Hydrometric Areas (1961-2012). NERC Environmental Information Data Centre. https://doi.org/10.5285/5e1792a0-ae95-4e77-bccd-2fb456112cc1 [4] Keller, V. D. J., Tanguy, M., Prosdocimi, I., Terry, J. A., Hitt, O., Cole, S. J., Fry, M., Morris, D. G., and Dixon, H.: CEH-GEAR: 1 km resolution daily and monthly areal rainfall estimates for the UK for hydrological use, Earth Syst. Sci. Data Discuss., 8, 83-112, doi:10.5194/essdd-8-83-2015, 2015. [5] Tanguy, M.; Dixon, H.; Prosdocimi, I.; Morris, D. G.; Keller, V. D. J. (2014). Gridded estimates of daily and monthly areal rainfall for the United Kingdom (1890-2012) [CEH-GEAR]. NERC Environmental Information Data Centre. https://doi.org/10.5285/5dc179dc-f692-49ba-9326-a6893a503f6e

Resource type

dataset

Resource locator

http://eidc.ceh.ac.uk/metadata/d8655cc9-b275-4e77-9e6c-1b16eee5c7d5/zip_export/

name: Supporting information

description: Supporting information available to assist in re-use of this dataset

function: information

Unique resource identifier

code

https://catalogue.ceh.ac.uk/id/d8655cc9-b275-4e77-9e6c-1b16eee5c7d5

codeSpace

doi:

Dataset language

eng

Spatial reference system

authority code

urn:ogc:def:crs:EPSG

code identifying the spatial reference system

27700

Classification of spatial data and services

Topic category

climatologyMeteorologyAtmosphere

Keywords

Keyword set

keyword value

Meteorological geographical features

originating controlled vocabulary

title

GEMET - INSPIRE themes, version 1.0

reference date

date type

publication

effective date

2008-06-01

Integrated Hydrological Units

Geographic location

West bounding longitude

-8.648

East bounding longitude

1.768

North bounding latitude

60.861

South bounding latitude

49.864

Temporal reference

Temporal extent

Begin position

1862-01-01

End position

2015-12-31

Dataset reference date

date type

publication

effective date

2017-02-23

date type

creation

effective date

2017-02-15

Frequency of update

unknown

Quality and validity

Lineage

SPI is calculated as originally defined in McKee et al. [1]. SPI is based on the cumulative probability of a given rainfall amount occurring at a location. The historic rainfall data of the station is fitted to a statistical distribution. For this dataset, the statistical distribution used is the gamma distribution, which has been extensively used and is recommended as a default choice for Europe by Stagge et al. [2]. The L-moments method was used to estimate the gamma distribution parameters, as the maximum likehood method was failing to fit a realistic distribution in some isolated cases (more details on the choice of methodology in Tanguy et al. [3]). To calculate SPI, the R package SCI was used (Gudmundsson & Stagge [4]), but modified to use L-moments (instead of Maximum Likelihood). The input data used is the monthly rainfall grids from the Met Office 5km gridded rainfall product provided within Historic Droughts project (grant number: NE/L01016X/1), which has been area-averaged over each of the Integrated Hydrological Units (IHU) Hydrometric Areas (Kral et al. [5]). [1] McKee, T. B., Doesken, N. J., Kleist, J. (1993). The Relationship of Drought Frequency and Duration to Time Scales. Eighth Conference on Applied Climatology, 17-22 January 1993, Anaheim, California. [2] Stagge, J. H., Tallaksen, L. M., Gudmundsson, L., Van Loon, A. F. and Stahl, K. (2015), Candidate Distributions for Climatological Drought Indices (SPI and SPEI). Int. J. Climatol. doi: 10.1002/joc.4267 [3] Tanguy et al. (2015), in preparation. [4] Gudmundsson, L. & Stagge, J. H. (2014). Package 'SCI': Standardized Climate Indices such as SPI, SRI or SPEI. Repository CRAN, http://cran.r-project.org/web/packages/SCI/SCI.pdf [5] Kral, F., Fry, M., Dixon, H. (2015). Integrated Hydrological Units of the United Kingdom: Hydrometric Areas without Coastline. NERC-Environmental Information Data Centre doi:10.5285/3a4e94fc-4c68-47eb-a217-adee2a6b02b3

Conformity

Data format

name of format

Comma-separated values (CSV)

version of format

unknown

Constraints related to access and use

Constraint set

Use constraints

If you reuse this data, you should cite: Tanguy, M., Fry, M., Svensson, C., Hannaford, J. (2017). Historic Standardised Precipitation Index time series for IHU Hydrometric Areas (1862-2015). NERC Environmental Information Data Centre https://doi.org/10.5285/d8655cc9-b275-4e77-9e6c-1b16eee5c7d5

Constraint set

Limitations on public access

superseded

custodian

Metadata on metadata

Metadata point of contact

organisation name

Environmental Information Data Centre

full postal address

Lancaster Environment Centre, Library Avenue, Bailrigg

Lancaster

LA1 4AP

email address

eidc@ceh.ac.uk

responsible party role

pointOfContact

Metadata date

2018-11-29T10:32:37

Metadata language

eng