Dygraph of Dublin Airport, University College Galway, Cork Airport, and Belfast weather stations

Explanation of data being used

The data that was used for this piece was of the 25 weather stations in Ireland. Each of these stations had corresponding data, which dated from 1850 to 2014, on monthly rainfall. This information was replaced as an R binary file for this exercise (Brunsdon, 2022). There were two corresponding objects of stations and rain. The station object contained information of these stations; elevation, latitude and longitude, location, and the source of the given information. The rain object consisted of information of the years, months, rainfall records, and each station (Brunsdon, 2022). The data in use in this piece had been modified into RCode to create individual stations of Belfast, Dublin Airport, University College Galway, and Cork Airport. These stations would then be manipulated into a dygraph, ranging from 1850 to 2014 on the monthly rainfall recorded at each station.  

Steps and RCode on creating the dygraph

This began by setting up our working directory, where the rainfall RData file would also be located.

Install all packages associated with the development of the dygraph; tidyverse and dygraphs.

library(tidyverse)
library(dygraphs)

To create a time series: 

rain %>% group_by(Year,Month) %>% filter(Station=="Dublin Airport") %>%
  summarise(Rainfall=sum(Rainfall)) %>% ungroup() %>% transmute(Rainfall) %>%
  ts(start=c(1850,1),freq=12) -> dub_ts

This began with grouping the rain object by Year and Month. It then pipelined this by filtering out the station. The transmute function filtered out only the necessary information which was the Rainfall category. The time series would start in 1850 with the first month of January. The frequency of these months would include all twelve months.  

This same process was repeated for the other three stations. The only difference would be the replacement of station names in the filter function, as seen in the following lines of code.

rain %>% group_by(Year,Month) %>% filter(Station=="Belfast") %>%
  summarise(Rainfall=sum(Rainfall)) %>% ungroup() %>% transmute(Rainfall) %>%
  ts(start=c(1850,1),freq=12) -> bel_ts
rain %>%group_by(Year,Month) %>% filter(Station=="Cork Airport") %>%
  summarise(Rainfall=sum(Rainfall)) %>% ungroup() %>% transmute(Rainfall) %>%
  ts(start=c(1850,1),freq=12) -> cork_ts
rain %>% group_by(Year,Month) %>% filter(Station=="University College Galway") %>%
  summarise(Rainfall=sum(Rainfall)) %>% ungroup() %>% transmute(Rainfall) %>%
  ts(start=c(1850,1),freq=12) -> gal_ts

With the four-time series created, it was then appropriate to create a dygraph of all four stations for comparison.  

To do this, the following RCode is needed: 

dub_ts %>% dygraph(width=800, height=130, group="dub_bel_cork_gal", main="Dublin") 

bel_ts %>% dygraph(width=800, height=130, group="dub_bel_cork_gal", main="Belfast")                   

cork_ts %>% dygraph(width=800, height=130, group="dub_bel_cork_gal", main="Cork")                 

gal_ts %>% dygraph(width=800, height=170, group="dub_bel_cork_gal", main="Galway") %>% dyRangeSelector() 

Using the dygraph function, the width of 800 and the height of 130 were selected. In the group output, the entitled “dub_bel_cork_gal” was chosen in which all four stations were included in the group. In the final line of code, the dyRangeSelector function was inserted, which adds a range selector that can control all station time series simultaneously.  

Brief discussion of patterns

From 1850, some extremities in rainfall records could be seen across all four weather stations. Winter months were said to have experienced the most rainfall compared to the summer months. One exception was December 1854, where numbers had seen lows of 9.9 in Cork and 16.1 in Belfast. It could be assumed that this would have been a colder winter, with frost and snow more prominent features than rainfall. Between 1890 and 1900s, there were some fluctuations noted in the recorded rainfall.  

From 1970 onwards, there was a steady increase in the amount of monthly rainfall. Recorded rainfall seen in December 1978 reached numbers of 217. Belfast witnessed figures of 329.5 in the same month of 1978. Cork noted sums of 264.9 that same December. In Galway, a figure of 151.5 was documented on the same date, being the lowest recorded figure of the winter months.

From the 2000s, numbers had increased greatly when compared to previous decades. An explanation for this would have been the increase in global mean temperatures and the severity of events that were accompanying this climate change. One example could be seen in the summer months of 2008. August 2008 had a recorded sum of 192.4 in Dublin, which was one of the highest noted monthly rainfall sums. In Belfast, this figure was said to be 255.3. Numbers of 240.2 in Galway and 165 in Cork were noted in August 2008. The result of these numbers were flash foods that were swept across the country (The Irish Times, 2009). 

2011 was one of the coldest winters on record to hit Ireland. Figures of 51.9 in Dublin, 67 in Cork, and 42.5 in Galway, had shown that rainfall sums were notably low due to the Arctic conditions that hit Ireland that year (Independent, 2011).  

In recent years, Cork had witnessed the highest recorded sum for February 2014 of 240.5, followed by Galway of 206.04, then Belfast, and Dublin. The reason for this was the devastating impacts of Storm Darwin that hit the country (Siggins, 2016). Rainfall records had not seen these heights since 2009 and before that, 2002. Therefore, it could be assumed that rainfall records might see numbers of such heights with the influence of global surface temperature rising following 2014.  

In conclusion, it could be said that weather events have reached significant heights in the winter months. This was expected with the colder conditions present in this season. With temperature rises becoming a renowned issue, these figures could hit unexpected numbers in years to come.  

References

Brunsdon, C. (2022) Looking at Time Series, GY672: Analyzing Spatial and Temporal Data Using R. 26 October 2022, Maynooth University.  

Independent (2011) December officially the coldest on record [online]. Available at: https://www.independent.ie/irish-news/december-officially-the-coldest-on-record-26611070.html (Accessed 14th January 2023).

Siggins, L. (2016) Ireland’s worst damage on record was in 2014: Storm Darwin’s devastating impact may have been due to a ‘sting jet’, expert says. Irish Times [online]. 25 November 2016. Available at: https://www.irishtimes.com/news/ireland/irish-news/ireland-s-worst-storm-damage-on-record-was-in-2014-1.2882706 (Accessed 14th November 2023).

The Irish Times (2009) Record levels of rainfall seen in 2008: Record levels of rainfall fell last year as heavy showers swept across the country, meteorologists said today. [online]. Available at: https://www.irishtimes.com/news/record-levels-of-rainfall-seen-in-2008-1.833700 (Accessed 14th November 2023).