Menu
Phenology Weekly
Living Almanac: Phenology Weekly - a US based phenology newspaper! You can access it on paper.li or linked within PEP725Living Almanac: Phenology Weekly
Remark: We think it's worth reading but PEP725 does not have any influence to the content of this newspaper!
Wednesday, November 13. 2013
4th PEP725 Management Meeting 2013, Reading/UK
Some of the presentations given at the 4th. PEP725 Management Meeting are now online - sorry for the delay.
Friday, August 23. 2013
Test of new visualization methods
You are right if you think reading is easier than doing so I spent the one or other evening for the creation of a working example with our PEP725 records. What I have done is to use the example of the streamgraph, adapt the JavaScript source and added some mouseover events. Together with some preprocessed datasets – that was the easy part – we have now the following new graph.
Due to the fact that nearly 90% of all records where contributed by the German colleagues I have to use a logarithmic scale to keep other countries visible. Well it’s only a qualitative representation of our content (so I skipped the y – axis) but nevertheless I think this kind of diagram is an excellent way showing the annual contribution of each national network.
So if you are curious try it (sorry Internet Explorer doesn’t work) Streamgraph of PEP725
Monday, August 12. 2013
Performance of tree phenology models...
Performance of tree phenology models along a bioclimatic gradient in Sweden. Ecological Modelling, 266: 103-117,Olsson, C., Bolmgren, K., Lindström, J., Jönsson, AM. 2013
Olsson et al. 2013
Thursday, July 11. 2013
Model Time-To-Event Data
Congratulation from our side!
Friday, February 15. 2013
Bud burst of birch in Finland and the UK
Friday, December 28. 2012
Dataset Update Austria
Thursday, November 22. 2012
What role for photoperiod in the bud burst phenology of European beech
Abstract:
A considerable number of studies have investigated the phenology of European beech using models, experimental controlled conditions, or descriptive surveys of patterns in situ. In spite of this interest, there is no consensus about the environmental factors controlling bud burst in beech, especially about the role of photoperiod and chilling temperature (cold temperature effective to release bud dormancy). However, recent experimental and modelling studies provide new insights into the means by which these environmental factors control beech phenology.
This present contribution aims to reconcile contradictory hypotheses about the main environmental factors controlling bud burst date of European beech. First, we review the main published results on the environmental control of beech phenology both in controlled and in natural conditions. Second, supported by the findings of recent studies, we propose a new theory for the role of photoperiod during the chilling phase for explaining spatial and temporal variations in bud burst phenology of European beech. Examples using long-term data from the Swiss Alps and Germany are presented to support this theory. The possible impacts of future and ongoing climate warming on beech phenology are discussed. Finally, due to interactions between chilling, forcing temperature, and photoperiod, we assert that beech phenology follows a nonlinear trend across biogeographical gradients such as changes in elevation or latitude and that the bud burst date of beech is expected not to undergo significant changes in response to global warming, especially in warmer climates.
European Journal of Forest Research
Thursday, September 20. 2012
Phenology 2012 Conference Poster
Monday, August 13. 2012
Dataset Update
Wednesday, June 20. 2012
Distribution of Observation Patterns in the PEP725 Database
- Figure 1: Mean annual distribution of observations in the PEP725 database
I thought it would also be interesting to look at a statistic about the weekdays of the observations. If we think about ideal observations we can assume that phenological phases are equally distributed over all days of the week. So 14.3% (100% / 7 days) of observations will be on Sundays, 14.3% on Mondays and so on. Observers with a 5 day week will probably only report during their shift; volunteer observers (citizen scientists) maybe more on weekends.
However, that's all only assumptions. Let us take a closer look at the millions of records in the international PEP725 data base. Unfortunately we do not store the weekday of an observation,. Actually we don’t even have a simple date in our records. What we have is the year and the day of the year. So we have to calculate the missing weekdays from the existing information. Our database system (MySQL) provides some handy functions for this task, e.g. DAYOFWEEK and DATE_ADD. The final SQL statement looks like this:
SELECT DAYOFWEEK( DATE_ADD( CONCAT( CAST( (year -1) AS CHAR ) , '-12-31' ) , INTERVAL `day` DAY) ) AS Weekday, count( * ) FROM `pep_data` GROUP BY Weekday 
- Figure 2: Result of the first analysis. It is obvidous that on Sunday we have fewer results in the database as, e.g. on Monday
The informative value Figure 2 is not very good,so I have calculated the relative percentage of each weekday and compared it to the ideal result of 14.3% (all observations are equally distributed over the week).
- Figure 3: Deviation of observation dates from the ideal result of 14.3%. It seems that on Monday late reports are not unusual and on Friday expected phenological events of the weekend will be reported prematurely.
Figure 3 shows the mean reporting practice over the whole PEP725 data set - now let's take a look if there are differences between single countries. For this analysis I’ve selected the members with the most stations: the United Kingdom (UK), Germany (DE), Austria (AT), the Netherlands (NL) and Switzerland (CH).
- Figure 4: Observations in Austria, Switzerland and Germany with a higher frequency during the week
Austria, Switzerland and Germany are very similar (Figure 4). Monday is always the busiest day of the week. Especially in Austria - it's the only day of the week with more records than expected. Switzerland looks like the generall PEP725 analysis with slightly higher amplitude. Beside the Sunday–Monday problem,Germanys observations are very well distributed over the week. Nearly the opposite case in the Netherlands and UK, probably due to the high numer of volunteer observers (NL Natuurkalender, UK natures's calendar) the weekends are over represented (Figure 5). It would be interesting to know the reason for the busy Monday in the UK
- Figure 5: Observations in the Netherlands an the UK have higher frequency during weekends
That brings us to one last question – the observation practice over time. The previous results were somehow expected, but it might be interesting if there is some kind of trend how we observe our nature. The PEP725 database reaches back to the year 1868, but there are only a few records available. From the year 1950 onwards we observe a fast development of phenological networks all over Europe with the peak in the 1980s. For that reason we will examine the early records all together and the later ones – those starting in the 1950s and onward.
- Figure 6: Observation pattern in the years before 1950.
For the period from 1868 until 1949 we can use about 14,000 observations. As we can see in Figure 6 the monitoring is very similar to the modern citizen scientist’s network as we have found in the Netherland’s records. It seems that volunteer observers are not an invention of recent years.
- Figure 7: Observations from 1950 until now. Again we look at the deviation from the expected 14.3% result. In the 1970s we have reached the peak of weekend observations with a tendency to a more uniform practice nowadays.
The occurrence of phenological phases strongly depend on local weather patterns, micro climate and adaption strategies of plants so it is very difficult to identify errors in the cloud of possible variation. The presented analysis of the relative number of observations per weekday shouldn’t be understood as a tool for quality control, but rather as a means for getting a feeling about different observer types and their behavior. If you have a large number of observations it is very interesting to see the influence of professionals and citizen scientists today and in the past.
Thursday, May 31. 2012
Dataset Updates 2012 Summary
Since the start of the year we can provide about 140 000 new phenological observations. About one half are new stations with records back to 1951 and 78 000 of them are updates for 2011. A huge number came from Germany and Switzerland, but also countries with smaller phenological networks contributed a lot of observations (until now Croatia, Czech Republic, Bosnia and Herzegovina and Italy)
Monday, March 26. 2012
Invitation: PEP725 Symposium
Tuesday, March 13. 2012
Station browser online
If you select the corresponding link from the main menu the first target is the country selection page with general information of all stations (in some cases spread to many subpages). If you now select one observation point you can see all details of this station and the map as well. In the second table on the left you can find the next three meteorological stations from the European Climate Assessment & Dataset Project.
Tuesday, March 6. 2012
Dataset Update
Monday, February 20. 2012
Temporal data coverage
There are quite many short living observation sites, 25% of all stations have 2 or less records, the upper quartile of station has more than 470 records.
