| 04 Sep 2026
Thermal conditions on the coast of Labrador during the late 19th/early 20th century
Abstract. The long-term Moravian missionary meteorological observations, conducted from the late 18th century until the 2nd World War, provide a unique perspective on climate conditions along the Labrador coast. The present paper focuses on the analysis of air temperature in the late 19th and early 20th centuries based on sub-daily observations (three to five times a day) available for six stations: Rama (1882–1890), Hebron (1882–1918), Okak (1883–1889), Nain (1882–1913, 1926–1939), Zoar (1882–1894), and Hopedale (Hoffenthal) (1882–1898). The meteorological observations were carried out by the missionaries on behalf of the Deutsche Seewarte and are preserved in the archives of Deutscher Wetterdienst (Germany).
Quality-controlled and corrected mean daily air temperature were used to calculate standard climatic characteristics, including monthly, seasonal, and annual means; climate continentality indices; day-to-day temperature variability; thermal seasons; and other characteristics. In addition to extending the climate analysis, a set of additional useful climatic indices was calculated, including Growing Degree Days (GDD), Air Thawing Index (ATI), Positive Degree Days (PDD), and Air Freezing Index (AFI). Historical temperature data from the coast of Labrador were compared with contemporary thermal conditions from 1990 to 2020. At Nain, the mean annual air temperature during 1882–1892 was 2.3 °C lower than during 1990–2020. The separate Nain record for the Early Twentieth Century Warming (1926–1939) remained 0.8 °C lower than the modern mean. At Hopedale, the mean annual temperature was −3.2 °C during 1882–1898 and −1.5 °C during 1990–2020, giving a historical–modern difference of −1.7 °C. At Nain, warmer temperature classes occurred more frequently during the modern period, particularly in autumn and summer, whereas the differences at Hopedale were most apparent in summer. The historical records also indicate a slightly greater annual temperature range and stronger climate continentality than in the modern period, with the largest temperature changes occurring during the cold season.
General comments:
Good introduction to previous works on understanding climate (temperature) variability on the Labrador Coast in the subarctic NA. Though the temperature data of 19th and 20th Century of the region has been collected and analysed before, this study attempts to generate diverse systematic temperature statistics to understand climate in the past, compared to modern period.
However, in its present state the article needs significant revisions and not suitable for publication. The analyses and visualizations made to support the assessments are ambiguous in general, and incoherent at places. Methodology used in the article is not well presented and lacks explanation on why/how these are used. Discussion and Conclusion sections lack focus and seamless quality expected in these sections.
Tables and Figures are mislabelled, and some are difficult to read, text doesn’t fully explain what they are and what a reader is expected to see and understand from them.
One obvious weakness is lack of homogenisation; several previous studies have used statistical analysis to find break points in the data records and corrected to adjust for site relocations and changes in instruments/observing techniques. Any historical study looking at the long-term climate change cannot fully asserted the findings without removing biases in the historical data.
Made no use of daily-data where more interesting features may lay.
Specific comments:
Fig 2 – x-axis seems busy, place ticks by multiples of 5yr or more.
[L230] Derivation of other MDAT formulae and values not clear, give more details
[L235] Its not entirely clear which corrections are applied to which stations, and for which months. Both Tables 2 and 3, follow same pattern. Its hard to see which months, or stations require larger adjustments. To make it clearer, I suggest making a plot which shows unadjusted monthly/daily values vs adjusted.
Fig3. – In panel (a) if Nain historical observations are being compared with Nain Modern data then why other stations’ data is shown, it distracts from making comparisons between historical vs modern Nain observations. Consider deleting other stations’ from the plot.
Table 4 – All stations except Nain have observations starting 1882/83, however, the difference is estimated between other stations and Nain which starts in 1926. I don’t understand what is learned from this exercise?
Figure 4 – Temperature indices (GDD, ATI, PDD and AFI) are calculated for Rama (1882–1890), but, the title for subplots suggest that historical and modern are being compared, which is not the case. There is another issue here: how similar are climatic conditions at Rama and Nain? Your own introduction explains that within short distances diverse micro-climates form, modulating weather observations taken at even at close sites. Requires co-variability assessment. Direct comparison without a valid qualifier is untenable.
Figure 5,6,8 – Ditto as in Figure 4
Figure 9 – Comparing historical and modern is valid for Hopedale but why AVG H is dot rather than line in panel (a) unlike other plots?
Figure 13,14 – Does panels show seasons or something else. Figure captions have been poor, and sometimes wrong. Please rewrite all captions where unclear.
Figure 16 – Cannot understand why LPF is applied to the data, even text doesn’t mention it.
[L534] Would be helpful to see what the criteria is
[L542] There is no Figure 21 in the MS.
And many more.
Discussion and Conclusion sections need major overhaul as the paragraphs seem unconnected and do not narrate unified understanding of the findings.
Overall suggestion is to analyse how other stations vary compared to Nain and Hopedale when they contain contemporary data. This comparison will help understand trends in other stations historical vs modern periods, without relying on unquantified similarity. Otherwise, perform and make assessments on stations which have both historical and modern data (e.g. Nain and Hopedale), withdraw the rest from the analysis.