C L I M AT E S E R V I C E C E N T E R G E R M A N Y
Site-Characteristic - Climate-Fact-Sheet
BASF production site Ludwigshafen
Summary and key findings
This site-characteristic Climate-Fact-Sheet has been compiled for the BASF production site Ludwigshafen, located in the southwestern part of
Germany. The region is characterized by a maritime temperate climate with warm summers and mild winters.
In this fact sheet projected climate change signals for a set of climate parameters have been summarized. The data is taken from 24 climate
change projections of regional climate models. All changes are calculated for the period until 2100 with respect to a 30-year reference period from
1971 to 2000. Spatially all climate change estimates are compiled over a region characteristic for the BASF production site.
For all analysed climate parameters/indices the magnitude of the projected climate change signals and additionally an expert judgement for the
signal strength and the confidence with regard to the specific change are provided.
In summary the changes projected by the ensemble of climate models for the end of the 21st century are summarized in the table below:
Climate parameter/index
Projected change signal
Confidence in projected change
More details
Annual mean temperature
Number of summer days
Number of hot days
Number of very hot days
Number of frost days
Moderate increase
Strong increase
Strong increase
Strong increase
Strong decrease
High confidence
High confidence
High confidence
Moderate confidence
High confidence
Number of ice days
Occurrence of moderate heatwaves
Maximum length of moderate heatwaves
Occurrence of strong heatwaves
Maximum length of strong heatwaves
Strong decrease
Strong increase
Strong increase
Strong increase
Moderate increase
High confidence
High confidence
Medium confidence
High confidence
Medium confidence
Frequency of extended dry spells
Annual precipitation sum
Summer precipitation sum
Winter precipitation sum
Precipitation intensity of very wet days
Moderate decrease
Moderate increase
Moderate decrease
Moderate increase
Moderate increase
Low confidence
High confidence
Medium confidence
High confidence
High confidence
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Precipitation intensity of extremely wet days
Moderate increase
Occurrence of above 25 mm/day precipitation days Moderate increase
High confidence
Medium confidence
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
1
Introduction to the concept of a site-characteristic Climate-Fact-Sheet
In this site-characteristic Climate-Fact-Sheet, the projected climate changes for a set of climate parameters are presented for a specific production site. The analysis of projected changes is based on an ensemble of 24 regional climate model projections following a moderate and a high
emission scenario pathway, respectively. Changes are analysed in a combined way by merging the simulations from the two emissions scenarios
as well as for each of the two scenarios separately.
In order to take into account that the simulations of a regional climate model are not site-specific, an area around the production site has been
defined, over which the changes are calculated as weighted means. Due to the fact, that the production site is located in a rather plain and homogenous inland region (Rhine Rift Valley) with a regionally rather uniform climate the closest nine gridboxes of each model simulation to the
production site have been selected for the analysis. A comparison between the real world and model world topographies around the production
site is depicted in the figure below. In this figure also the geographical location of the BASF production site Ludwigshafen is highlighted. More
details on the climatological characteristics of the production site are given in the subsequent section.
In this site-characteristic Climate-Fact-Sheet projected changes for the 21st century are presented, with respect to the reference period from 1971
to 2000. Today’s climate characteristics are included on the basis of available observations. The quality of the analysed climate change simulations to reproduce today’s climate are included in an expert judgment on the confidence of projected changes. For each climate parameter presented here a short definition is provided.
A detailed explanation of the figures depicted in this site-characteristic Climate-Fact-Sheet is given on the following page. More information on the
model simulations, the weighting of the data and the details of the expert judgment procedure are given on the last page.
Climatological and site-specific characteristics of the BASF production site Ludwigshafen
The BASF production site in Ludwigshafen is located in the Rhine Rift Valley in the southwestern part of Germany. The production site is directly
at the river Rhine (western shore) at an altitude of 96 m a.s.l. The climate of the region can be characterized as maritime temperate climate of
the mid-latitudes (Cfd) with generally warm summers and mild winters (see climate diagram in the lower right, which is based on local station data
for the period from 1995 to 2012; The red line represents the monthly mean temperature at the station and the blue line the monthly precipitation
sum, respectively. The light blue shaded area reflects the humid conditions throughout the year). Due to frequent influence of the Mediterranean
air masses the Rhine Rift Valley region is known to be the mildest region in Germany.
Based on local station measurements of BASF the annual mean temperature at the BASF production site in Ludwigshafen is 11.3 °C. The average daily maximum temperature in summer rises to 26 °C while the average daily minimum temperature in winter falls to just below zero degrees.
Annual mean total precipitation is approximately 565 mm, with precipitation occurring in all months
of the year. Maximum amount of precipitation falls in the months of May to August with around
65.1 mm/month.
Observed annual mean temperature trend since 1881 in the greater region is for an increase of
1.4 °C, which is an above average increase in temperature compared to the other parts of Germany.
The mean temperatures of the meteorological seasons show a similar temperature trend but are
highest in summer and autumn. Observed annual precipitation amounts in the greater region also
slightly increased in the past (11 % over the period since 1981), with winter precipitation increasing
and summer precipitation slightly decreasing (Source for trends: German Weather Service*).
Recent extreme events in the region have been reported for the years 2003 and 2006 (extremely hot
summers and in 2003 additionally extreme low flows) and 2013 (flood event in June).
* taken from: „Zahlen und Fakten zum Klimawandel in Deutschland; Klima-Pressekonferenz des Deutschen
Wetterdienstes am 25. März 2014 in Berlin“
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
2
How to read the figures in this site-characteristic Climate-Fact-Sheet
Climate change projection diagram
Unit
and
scale
of
projected
change
of
the respective climate
parameter.
Time axis of the projected evolution over the 21st century (left part
of diagram) and for the three 30year time periods (right part of the
diagram).
Left part of the diagram ...
Right part of the diagram ...
shows the bandwidth of projected climate changes for a given
parameter throughout the 21st century with respect to the reference period from 1971 to 2000. Note, that only 30 year running
mean values are depicted which explains, why only the period
from 2005 to 2086 is shown (e.g. the year 2086 represents the
period form 2071 to 2100). The three different components of the
figure are:
shows the bandwidth of projected climate changes for a given parameter as a mean over 30 years for three specific time periods (2006-35;
2036-65; 2071-00) with respect to the reference period from 1971 to
2000. For each of the three time periods the following information is
provided by the bars in different colours:
The light-blue band in the background depicts the
“full range“ of projected changes of all analysed
projections of both scenarios combined.
The blue-bars represent the same information as is given on the
left hand of the figure, but for the three respective time periods.
The “full range“ is given in light-blue; the “likely range“ is given
in dark-blue and the median is given in turquoise - each for both
emission scenarios combined.
The dark-blue band on top of the light-blue band
depicts the “likely range“ of projected changes of
all analysed projections of both scenarios combined. The “likely range“ is defined by 66 % of all
projections centred around the median.
The yellow-bars depict the “full range“ of projected changes for
the moderate emission scenario for the three respective time periods. The turquoise line in the foreground here depicts the median of projected changes of the respective projections and time
periods.
The turquoise line in the foreground depicts the
median of projected changes of all analysed projections of both scenarios combined. The median
is defined as the value, where 50 % off all projections are above and below, respectively.
The red-bars depict the “full range“ of projected changes for the
high emission scenario for the three respective time periods. The
turquoise line in the foreground here depicts the median of projected changes of the respective projections and time periods.
Note: The concept of a “likely range“ of change in order to characterise the bandwith of climate change projections is explained in more detail
in the info box on page 7 of this site-characteristic Climate-Fact-Sheet.
Expert judgment figures
For each climate parameter an “expert judgment“ on the projected changes is provided. The judgment is
separated into an estimate for the strength of the projected changes (“thermometer“ on the left side of the
diagram) and an estimate for the confidence with regard to the projected changes (“pointer diagram“ on
the right side of the figure). Each judgment is sub-dived into three levels and depends on a set of different
criteria, as briefly described below *:
Signal strength
•separated into weak (one blue square); moderate (two blue squares) and strong (three blue squares)
signals (example shows a moderate signal)
•depends on the magnitude of projected changes and the statistical significance of the changes
* More details on the signal
strength and confidence measures can be found on the last
page of this document
Confidence
•separated into low (horizontal arrow); medium (diagonal arrow) and high (vertical arrow) confidence (example shows a medium confidence into the projected changes)
•depends on the agreement of projected changes and the ability of the models to simulate today‘s climate
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
3
Projections of annual mean temperature, summer days, hot days and very hot days as well
as frost days and ice days (for definition of climate parameter see box at the bottom of respective page)
Annual mean temperature
• Observed average annual mean temperature for the period 1971
to 2000 is 11.3 °C.
• Median projection of change in annual mean temperature is for an
increase of +2.6 °C by the end of the century *.
• Likely range: +1.7 to +3.5 °C; full range: +1.3 to +4.6 °C
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +1.8 °C
• High-Scenario: Median +3.3 °C
© GERICS, 2015
Annual number of summer days
• Observed average annual number of summer days for the period
1971 to 2000 is 43 days.
• Median projection of change in annual number of summer days is
for an increase of +24 days by the end of the century.
• Likely range: +15 to +42 days; full range: +10 to +52 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +15 days
• High-Scenario: Median +34 days
© GERICS, 2015
Annual number of hot days
• Observed average annual number of hot days for the period 1971
to 2000 is 9 days.
• Median projection of change in annual number of hot days is for an
increase of +12 days by the end of the century.
• Likely range: +6 to +20 days; full range: +2 to +42 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +8 days
• High-Scenario: Median +16 days
© GERICS, 2015
Annual number of very hot days
• Statistically, the observed average annual number of very hot days
for the period 1971 to 2000 is 0.3 days.
• Median projection of change in annual number of very hot days is
for an increase of +2.8 days by the end of the century.
• Likely range: +0.9 to +9.6 days; full range: ±0 to +23.0 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +1.0 days
• High-Scenario: Median +3.5 days
© GERICS, 2015
Annual mean temperature is calculated on the basis of daily near-surface (2 m above surface) temperature data.
Annual number of summer days is the amount of days in a year, which have a daily maximum temperature equal or
higher than 25 °C.
Annual number of hot days is the amount of days in a year, which have a daily maximum temperature equal or higher
than 30 °C.
Annual number of very hot days is the amount of days in a year, which have a daily maximum temperature equal or
higher than 35 °C.
* Note that “end of the century“ refers to the 30 year period from 2071 to 2100 throughout the fact sheet.
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
4
Annual number of frost days
• Observed average annual number of frost days for the period 1971
to 2000 is 68 days.
• Median projection of change in annual number of frost days is for a
decrease of -36 days by the end of the century.
• Likely range: -49 to -28 days; full range: -63 to -13 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median -31 days
• High-Scenario: Median -45 days
© GERICS, 2015
Annual number of ice days
• Observed average annual number of ice days for the period 1971
to 2000 is 15 days.
• Median projection of change in annual number of ice days is for a
decrease of -10 days by the end of the century.
• Likely range: -14 to -7 days; full range: -16 to -5 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median -9 days
• High-Scenario: Median -14 days
© GERICS, 2015
Projections of occurrence and length of heatwaves
Occurrence of moderate heatwaves
(for definition of climate parameter see box at the bottom of respective page)
• Observed average annual occurrence of moderate heatwaves for
the period 1971 to 2000 is 2.6 events per year.
• Median projection of change in mean annual occurrence of moderate
heatwaves is for an increase of +1.5 events by the end of the century.
• Likely range: +1.1 to +2.7 events; full range: +0.1 to +2.9 events
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +1.1 events
• High-Scenario: Median +2.1 events
© GERICS, 2015
Maximum length of moderate heatwaves
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Observed average annual maximum length of moderate heatwaves for the period 1971 to 2000 is 12 days.
• Median projection of change in annual maximum length of moderate
heatwaves is for an extension of +8 days by the end of the century.
• Likely range: +5 to +13 days; full range: +2 to +27 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +5 days
• High-Scenario: Median +9 days
© GERICS, 2015
Annual number of frost days is the amount of days in a year, which have a daily minimum temperature below freezing
point (below 0 °C).
Annual number of ice days is the amount of days in a year, which have a daily maximum temperature below freezing
point (below 0 °C).
Moderate heatwaves are defined as at least five consecutive days with daily maximum temperature of more than 25 °C.
Strong heatwaves are defined as at least five consecutive days with daily maximum temperature of more than 30 °C.
The occurrence depicts how often heatwaves of specific intensity/strength occur on average within one year. The maximum length of a specific heatwave defines the largest single event within each year.
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
5
Occurrence of strong heatwaves
• Statistically, the observed average annual occurrence of strong
heatwaves for the period 1971 to 2000 is 0.3 events per year.
• Median projection of change in mean annual occurrence of strong
heatwaves is for an increase of +0.8 events by the end of the century.
• Likely range: +0.3 to +1.6 events; full range: +0.1 to +2.7 events
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +0.4 events
• High-Scenario: Median +1.0 events
© GERICS, 2015
Maximum length of strong heatwaves
• Observed average annual maximum length of strong heatwaves
for the period 1971 to 2000 is 7 days.
• Median projection of change in annual maximum length of strong
heatwaves is for an extension of around +2 days by the end of the
century, but a few model projections also show a decrease.
• Likely range: ±0 to +4 days; full range: -0.5 to +12 days
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +1 day
• High-Scenario: Median +2 days
© GERICS, 2015
Projections of possible development of extended dry spells
(for definition see box below)
Occurrence of days with long-term drought characteristics (DLTDC)
• Statistically, the observed average annual occurrence of extended
dry spells for the period 1971 to 2000 is 8.7 days with long-term
drought characteristics (DLTDC).
Note: In contrast to all other change figures shown
here the spread in this figure is mainly caused by
a very strong temporal variability in the data of all
models and not because individual models disagreeing. The large year to year variability is linked
to the fact that very rare events are presented.
• Median projection of change in the occurrence of extended dry
spells is for a decrease of around -2.7 DLTDC per year by the end of
the century, but some model projections also show an increase.
• Likely range: -5.4 to +4.8 DLTDC; full range: -6.9 to +18.1 DLTDC
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median -4.3 DLTDC
• High-Scenario: Median -1.8 DLTDC
© GERICS, 2015
Extended dry spells are defined based on the Standardized Precipitation Index (SPI) in a way that the 2003 dry spell is reproduced. The SPI is a simple but accepted approach for monitoring meteorological drought applied by many weather services and
approved by the World Meteorological Organization (WMO). It is a probability index considering precipitation only for estimating
water supply, thus, identifying precipitation deficits or meteorological droughts as well as their intensities for various time scales. For
this site-characteristic Climate-Fact-Sheet, the SPI is used to estimate precipitation deficits specifically for a simplified Upper-Rhine
catchment (see figure on the right) being the principal reservoir and water supply for the BASF production site Ludwigshafen. Recent extreme events, such as the European heat wave and summer drought in 2003, impact tremendously on water supply levels,
thus, leading to water scarcity. This event can be reproduced – in intensity and instance of time – by computing the SPI based on
daily precipitation observations with a memory of six months. This means that for each day of the year the cumulative precipitation
of the previous 180 days is compared to the mean 180-day precipitation sum over the reference period. The larger the deficit in this
precipitation sum, the more negative the SPI will be. For the 2003 event the respective SPI value based on observed daily precipitation is -2.1. This SPI-value approximately represents the 2nd percentile of all SPI values during the reference period, and thereby
represents the rather extreme nature of the 2003 event as 98% of all days have a lower precipitation deficit.
By picking the 2nd percentile of today’s SPI the number of days with a long-term (180 days) water deficit can also be estimated on
the basis of regional climate model simulations for current and future conditions. These days with a long-term water deficit can either
be single days or –more likely- consecutive days representing a period with meteorological drought characteristics.
Simplified Figure of
the Upper- Rhine
catchment:
The red dot indicates
the position of the
BASF production site
Ludwigshafen.
The grey area represents the region, over
which the SPI has
been calculated.
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
6
Projections of annual, summer and winter precipitation sum (for definition of climate parameter see box at Annual precipitation sum
the bottom of this page)
• Observed average annual precipitation sum for the period 1971 to
2000 is 565 mm.
• Median projection of change in annual precipitation sum is for a
slight increase of +7 % by the end of the century, but a few model
projections also show a decrease.
• Likely range: +3 to +16 %; full range: -1 to +30 %
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +4 %
• High-Scenario: Median +8 %
© GERICS, 2015
Summer precipitation sum
• Observed average summer precipitation sum for the period 1971
to 2000 is 197 mm.
• Median projection of change in summer precipitation sum is for a
slight decrease of -9 % by the end of the century, but some model
projections also show an increase.
• Likely range: -19 to +11 %; full range: -23 to +36 %
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median -3 %
• High-Scenario: Median -19 %
© GERICS, 2015
Winter precipitation sum
• Observed average winter precipitation sum for the period 1971 to
2000 is 154 mm.
• Median projection of change in winter precipitation sum is for an
increase of +19 % by the end of the century, but a few model projections also show a decrease.
• Likely range: +9 to +32 %; full range: -3 to +44 %
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +14 %
• High-Scenario: Median +21 %
© GERICS, 2015
Depicting the bandwidth of climate change projections - the concept of a “likely range” of change
Information on projected climate change in this site-characteristic Climate-Fact-Sheet is based on a set of 24 regional climate change projections. Each climate change projections slightly projects a different climate changes signal. As all individual projections in principle have
the same chance to represent or not to represent the truth about the future climate development, all projected changes are included into the
analysis with the same weight. Therefore it is not possible to present a single value of change and so a bandwidth of potential changes is
given. This bandwidth is referred to as the full range in the climate change figures and depicted by the light-blue band.
In order to get a feeling of the potential likelihood of changes a widely used method is to define ranges where many models agree. In general
the idea is that ranges of changes depicted by many models are more likely to occur as values of change of single outliers. This aspect is
also applied here. In order to subdivide the full bandwidth of change we introduce the so called “likely range” (depicted as the central darkblue band in the climate change figures), which is defined by 2/3 (66 %) of all projected changes centred around the central value of change.
In our case the projected change of 16 out of 24 simulations lies within the “likely range”, whereas the four projections with highest and the
four projections with the lowest changes are outside of this range.
If the full range of all changes spans a much larger area than the “likely range” (either in one direction or in both), we can conclude, that a few
outlier model simulations project changes much different from the majority of the models. On the other hand a small discrepancy between
full and “likely range” indicates a large model agreement.
Annual, summer and winter precipitation sum are calculated on the basis of daily precipitation data
and include rain and snow precipitation. Seasonal precipitation is calculated based on the meteorological
year. Therefore, summer precipitation is the sum for the months June to August; winter precipitation is
the sum for the months December to February.
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
7
Projections of intensity and frequency of heavy precipitation events (for definition of climate parameter see box at the bottom of this page)
Intensity and frequency of precipitation of very wet days
• Observed average intensity of very wet days for the period 1971 to
2000 is 14.6 mm/day.
• Median projection of change in the intensity of very wet days is for
an increase of +10 % by the end of the century.
• Likely range: +6 to +20 %; full range: +1 to +26 %
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +7 %
• High-Scenario: Median +12 %
© GERICS, 2015
• Statistically, the observed average frequency of very wet days during the period 1971 to 2000 is 6.5 days per year.
• Median projection of change in the frequency of very wet days is for an increase of +1.8 days per year by the end of the century. Likely range:
+1.2 to +3.7 days per year; full range: +0.1 to +5.7 days per year.
• A stronger increase of very wet days is projected for the High-Scenario (Median: +2.3 days per year) compared to the Moderate-Scenario
(Median: +1.5 days per year).
Intensity and frequency of precipitation of extremely wet days
• Observed average intensity of extremely wet days for the period
1971 to 2000 is 22.8 mm/day.
• Median projection of change in the intensity of extremely wet days
is for an increase of +13 % by the end of the century, but a few
model projections also show a decrease.
• Likely range: +8 to +26 %; full range: -2 to +38 %
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +11 %
• High-Scenario: Median +16 %
© GERICS, 2015
• Statistically, the observed average frequency of extremely wet days during the period 1971 to 2000 is 1.3 days per year.
• Median projection of change in the frequency of extremely wet days is for an increase of +0.7 days per year by the end of the century. Likely
range: +0.3 to +1.7 days per year; full range: ±0 to +2.2 days per year.
• A stronger increase of extremely wet days is projected for the High-Scenario (Median: +0.8 days per year) compared to the Moderate-Scenario
(Median: +0.5 days per year).
Occurrence of above 25 mm/day precipitation days
• Statistically, the observed average annual occurrence of above
25 mm/day precipitation events for the period 1971 to 2000 is 0.9
events per year.
• Median projection of change in the frequency of above 25 mm/day
precipitation events is for an increase of +0.9 events per year by
the end of the century.
• Likely range: +0.3 to +1.6 events per year; full range: +0.2 to +2.5
events per year
Separate scenario examination for the period 2071 to 2100:
• Moderate-Scenario: Median +0.5 events per year
• High-Scenario: Median +1.1 events per year
© GERICS, 2015
The amount of rain falling on a very wet day and an extremely wet day is defined on the basis of the rainfall characteristics of the period 1971 to 2000.
A very wet day is defined as a day having an amount of precipitation higher than 95 % of all rainy days in the period from
1971 to 2000. Thus it belongs to the 5 % wettest days of present day climate (only wet days considered).
A extremely wet day is defined as a day having an amount of precipitation higher than 99 % of all rainy days in the period
from 1971 to 2000. Thus it belongs to the 1 % wettest days of present day climate (only wet days considered).
Above 25 mm/day precipitation days are days with a daily precipitation sum (either rainfall or snow) above 25 mm.
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
8
Expert Information
Data basis
All climate change projections presented here in this factsheet are based on an ensemble of dynamically downscaled
regional climate change projections compiled within the EURO-CORDEX initiative (http://www.euro-cordex.net). Altogether 24 climate projections have been analysed, separated into
12 projections for the medium emission scenario (RCP4.5)
and 12 for the high emission scenario (RCP 8.5). The ensemble consists of simulations from five different regional climate
models (RCM) which are forced by seven different global climate models (GCM) or global climate model realizations, respectively. An overview on the regional models, the respective
forcing model and scenario is given in the table.
For all parameters/indices based on temperature an initial
height correction has been conducted to account for slight differences in the topography of the models.
Moderate emission scenario (RCP45)
Name/Realization
Name of RCM
of forcing GCM
REMO
CCLM4.8
RCA4
CCLM4.8
RCA4
CCLM4.8
RCA4
RACMO2.2
HIRHAM5
WRF3.3.1
RCA4
RCA4
MPI-ESM; r1
MPI-ESM; r1
MPI-ESM; r1
CNRM-CM5; r1
CNRM-CM5; r1
EC-EARTH; r12
EC-EARTH; r12
EC-EARTH; r1
EC-EARTH; r3
IPSL-CM5A; r1
IPSL-CM5A; r1
HadGEM2; r1
High emission scenario (RCP85)
Name/Realization
of forcing GCM
Name of RCM
REMO
CCLM4.8
RCA4
CCLM4.8
RCA4
CCLM4.8
RCA4
RACMO2.2
HIRHAM5
WRF3.3.1
RCA4
RCA4
MPI-ESM; r1
MPI-ESM; r1
MPI-ESM; r1
CNRM-CM5; r1
CNRM-CM5; r1
EC-EARTH; r12
EC-EARTH; r12
EC-EARTH; r1
EC-EARTH; r3
IPSL-CM5A; r1
IPSL-CM5A; r1
HadGEM2; r1
Selection of representative grid boxes
No further dynamical or statistical downscaling has been made to extract the climate change information from the re- Schematic of gridgional model simulations for the specific production site. To get the information for the specific location for all presented
box weigthing
climate parameters except the drought indicators, the closest nine gridboxes centred on the production cite have been
extracted. Out of these nine boxes a weighted mean (with highest weight in the centre and lower weights at the boundaries – see schematic on the right) has been calculated. Therefore the information presented in the fact-sheet is not a
point information, but spans an area of approx. 36 km x 36 km. This is necessary, as the information obtained from a
regional model is not fully gridbox specific. In order to test how variable the projected climate change signal is within the
nine model grid-boxes a spatial variability test has been applied. The information on this test is included in the expert
judgment and described in detail below. The method to extract the closest nine grid-boxes is not uniformly applicable to
all production sites in the world. For sites at the coast or in mountainous areas other approaches might be considered
to define representative regions.
For the drought indicator, the catchment area of the river Rhine upstream of the production site has been considered because a drought that
affects the production site has to be a regional scale phenomenon.
Expert judgment on signal strength and confidence
For the signal strength the magnitude of the absolute value of the climate change signal at the end of the century and the statistical significance of the projected changes (also at the end of the century) are considered.
For the magnitude, fixed thresholds are given (see table). For the statistical significance a Mann-Whitney-Wilcoxon test or U-test has been
applied to test the null hypothesis that the distribution of a given climate parameter simulated by an individual model for today differs from
the distribution which is projected for the future. The confidence level applied for the significance test is 0.85.
The magnitude and the statistical significance are tested on the basis of the individual model simulations. In order to classify a projected
change as strong, it has to fulfil the threshold criteria and it has to be statistically sigSignal Strength
Magnitude
Significance
nificant. If the projected changes are above the threshold, but are not significant, it is
(of individual
of projected
of projected
classified as medium. The opposite applies if the signal is to be classified as weak.
projection)
change
change
Here the change has to be below the lower threshold criteria and has to be statistiWeak
<1.5 °C ; < 15 %
no
cally insignificant. If the change is significant although below the lower threshold it is
classified as medium. In the end the individual signal strengths of all simulations are
≥1,5 °C - ≤ 3,5 °C;
Moderate
yes or no
≥15 % - ≤ 40 %
combined into ensemble signal strength. To classify the ensemble signal strength as
strong/weak at least 66 % of all analysed simulations (independent of the emission
Strong
> 3,5 °C ; > 40 %
yes
scenario) have to be strong/weak signal. Otherwise the signal is classified as medium.
To estimate the confidence in the projected changes three individual tests have been applied to each model simulation (tests 1 and 2) and
to the full ensemble. These tests are as follows and described in more detail on the next page
(1) The ability of the models to represent today’s climate at the BASF production site Ludwigshafen is tested.
(2) The spatial agreement of projected climate change signals within the selected representative grid boxes as well as with a few surrounding grid boxes is tested.
(3) The direction of change of the individual climate change signals at the end of the century is tested.
For each of the three tests an individual rating (from 1 = poor to 3 = good) is achieved. Finally all individual ratings are then combined into an overall
rating. For this purpose, the rounded arithmetic mean of the individual test ratings is calculated. The results of this overall ranking is then classified into the three confidence levels as follows: rounded average rating of 1 = low confidence; rounded average rating of 2 = medium confidence;
rounded average rating of 3 = high confidence.
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
9
(1) Validation against observations
To test the ability of the models to represent today’s climate the simulations are compared to the local measurements at the production site
and the EOBS gridded observational dataset (http://www.ecad.eu/e-obs) for the period from 1971 to 2000. In general the mean bias and the
representation of the interannual seasonality are tested individually. For temperature and precipitation additionally the model’s representation of the seasonal cycle is taken into account. The critera for the validation tests are as follows:
(i) Mean bias: The mean bias of each individual model simulation to the observations is calculated for the 30-year validation period. If the bias
is smaller than 1 °C (in the case of temperature) or 15 % (for all other climate parameters), the simulation is rated as good, if the respective
bias is larger than 1 °C or 15 % but smaller than 3 °C or 40 % the quality of the simulation is rated as medium, and for all other cases the
simulation is rated as poor.
(ii) Interannual variability: In order to estimate if year to year fluctuations in the climate parameters can
be reproduced by the climate model simulations this test is conducted. Here, the ratio of the interannual
variability of the model simulation and the observed one is calculated. The interannual variability is the
standard deviation of the annual means of the respective climate parameter over the 30-year validation
period. Therefore, the ratio of the interannual variability can be expressed as:
Ratio of internal
variability
(Ratio Var)
Rating
≥ 0.9 & < 1.1
good (3)
≥ 0.67 & < 0.9
or
≥ 1.1 & < 1.33
medium (2)
< 0,67 or > 1.33
poor (1)
If the simulated variability deviates less than 10 % from the observed one, the simulation is rated as
good, if the deviation is less than 33 %, it is rated as medium, and for larger deviations it is rated as poor.
(iii) Seasonal Cycle: For the indices for temperature and precipitation additionally the representation of the mean annual cycle by the model
simulations is investigated. The test is based on monthly mean data but only applied if the observed difference between the warmest/coldest
is more than 1 °C or between the wettest/driest month is larger than 15 % respectively. To judge on the quality of the simulations, the rootmean-square error (RMSE) of the (30-year) mean annual cycle with removed mean bias is calculated. If the RMSE is smaller than 1 °C (in
the case of temperature) or 15 % (in the case of precipitation), the simulation is rated as good. If the respective RMSE is larger than 1 °C or
15 % but smaller than 3 °C or 40 % the quality of the simulation is rated as medium, and for all other cases the simulation is rated as poor.
To combine all the individual validation ratings the following two steps are conducted. First for each individual test, the rating represented of
at least 66 % of all model simulations is taken as the overall test ranking. If there is no ranking, for which at least 66 % of all model simulations give the same ranking, the overall ranking is set to medium (2). Second, the overall validation ranking is calculated as the rounded
arithmetic mean of the estimated individual test ratings. It has to be kept in mind, that for temperature and precipitation three individual tests
are performed, for all other parameters only two.
(2) Spatial agreement of projected climate change signals
The spatial variation of the climate change signals within the selected nine gridboxes around the specific production site as well as some
additional neighbouring grid boxes is also used as a measure of the reliability of the climate change signal. The lower the spatial variability
(noise) the more trustworthy is the projected change. However spatial gradients have to be captured by the method. To distinguish between
noise and a possible gradient in the signal a two-dimensional plane is fitted through the 7x7 gridboxes surrounding the specific production
site. The signal-to-noise ratio is determined as the ratio of the climate-change signal and the spatial standard deviation of the residual signal
(after removal of the gradient) both calculated for these 7x7 gridboxes. We set a threshold of 2 in order to pass the signal-to-noise test. If
more than 66 % of the simulations have a signal-to-noise ratio above 2, the signal is considered as lowly varying and therefore rated as good
(3). If the fraction of simulations is between 33 % and 66 % , the rating is medium (2). Finally, if less than 33 % of the simulations have a
signal-to-noise ratio higher than 2, the rating is poor (1).
(3) The direction of change of the individual climate change signals
The robustness of the signal is determined by evaluating both the agreement of the sign of the signal among the simulations and the ensemble spread. If more than 90 % of the simulations agree in the sign of change or the spread of the central 90 % of the simulations is less
than 1 °C or 15 %, the robustness is considered as high (3). If less than 66 % of the simulations agree in the sign of change or the spread
of the inner 90 % of the simulations is larger than 3 °C or 40 %, the robustness is considered as low (1). For all other cases the robustness
is considered as medium (2).
Note: This site-characteristic Climate-Fact-Sheet was created to fit the purpose of the ordering company BASF SE. Therefore the selection of
climate parameters as well as the visualization of the results have been adapted to support the needs of BASF SE.
The contents of this site-characteristic Climate-Fact-Sheet and the underlying data were processed and carefully checked according to the current state of science and technology. The Climate Service Center Germany (GERICS) only generated some of the climate change data on which
this site-characteristic Climate-Fact-Sheet is based on. The additional climate model data was downloaded and processed from the public ESGF
archive. GERICS shall not assume any liability for the topicality, correctness, completeness or quality of the provided information. GERICS also
assumes no liability for any decisions and their consequences, which are based on the use of this site-characteristic Climate-Fact-Sheet.
Ordering party:
BASF SE
67056 Ludwigshafen
Contact details of editors:
Climate Service Center Germany
Fischertwiete 1
D-20095 Hamburg
www.climate-service-center.de
© Climate Service Center Germany, October 2015
Site-characteristic Climate-Fact-Sheet
BASF production site Ludwigshafen
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