Lightning and fire weather in eastern coastal fynbos shrublands: seasonality and long-term trends

2013 ◽  
Vol 22 (3) ◽  
pp. 288 ◽  
Author(s):  
Tineke Kraaij ◽  
Richard M. Cowling ◽  
Brian W. van Wilgen
Keyword(s):  
Fire Regime ◽  
Temporal Trends ◽  
Fire Danger ◽  
Weather Data ◽  
Lightning Strike ◽  
The South ◽  
South Eastern ◽  
Daily Weather Data ◽  
Cloud To Ground Lightning ◽  
Season Of Burn

Daily weather data (since 1939) from four localities in the south-eastern, coastal part of the Cape Floral Kingdom (‘south-eastern-CFK’) were used to calculate daily fire danger indices (FDIs). Cloud-to-ground lightning strike distributions (2006–10) were explored for geographical and temporal trends. Low or moderate fire danger conditions were the norm year round, and even large fires occurred under these conditions. Lightning occurred throughout the landscape at fairly low densities (mean = 0.4 strikes km–2 year–1) and in all seasons, increasing somewhat during summer. Lightning presence increased with increasing rainfall, relative humidity, temperature and wind speed. Lightning seasonality in the south-eastern-CFK did not differ from that in the south-western-CFK. Our results provide evidence of a largely aseasonal fire regime in eastern coastal fynbos shrublands: FDIs peaked in winter (due to low rainfall and hot, dry katabatic winds) but were not associated with a winter fire regime; lightning and the co-occurrence of lightning and elevated FDIs were aseasonal and were correlated with the incidence of lightning-ignited fires throughout the year. The implication for management is that season of burn is largely unimportant. Mean annual FDI increased significantly over the study period, a trend which is likely to manifest in increased frequency and severity of fire, some of which has already been observed.

Evaluating the applicability of predicting dead fine fuel moisture based on the hourly Fine Fuel Moisture Code in the south-eastern Xing’an Mountains of China

2017 ◽  
Vol 26 (2) ◽  
pp. 167 ◽  
Author(s):  
Jili Zhang ◽  
Xiaoyang Cui ◽  
Rui Wei ◽  
Yan Huang ◽  
Xueying Di
Keyword(s):  
Scots Pine ◽  
Forest Floor ◽  
Loss Rate ◽  
Weather Data ◽  
Fuel Moisture ◽  
The South ◽  
Fire Control ◽  
South Eastern ◽  
Great Xing’An Mountains ◽  
Observation Period

To evaluate the applicability of the hourly Fine Fuel Moisture Code (FFMC) to the south-eastern Great Xing’an Mountains, dead fine fuel moisture (Mf) was observed under less-sheltered and sheltered conditions in Scots pine (Pinus sylvestris var. mongolica), larch (Larix gmelinii) and oak (Quercus mongolicus) stands during the summer and autumn of 2014. Standard FFMC and locally calibrated FFMC values calculated hourly were tested using Mf observations and weather data, and the results showed that the Mf loss rate in the less-sheltered forest floor was markedly higher than that in the sheltered forest floor (P < 0.05). The standard hourly FFMC underestimated Mf, especially in stands of larch, the dominant species in the Great Xing’an Mountains, and Mf for rainy days in Scots pine and oak stands. However, the calibrated hourly FFMC predicted Mf in all three forest stands very well (R2 ranged from 0.920 to 0.969; mean absolute errorfrom 2.93 to 6.93, and root-mean-squared errorfrom 4.09 to 7.87), which suggested that it was sufficiently robust for those stands around the observation period. This study will improve the accuracy of Mf predictions to aid fire control efforts in the Great Xing’an Mountains and provide a basis for hourly FFMC model calibration.

On the comparative importance of fire danger rating indices and their integration with spatial and temporal variables for predicting daily human-caused fire occurrences in Spain

2011 ◽  
Vol 20 (1) ◽  
pp. 46 ◽  
Author(s):  
M. Padilla ◽  
C. Vega-García
Keyword(s):  
Forest Fires ◽  
Fire Danger ◽  
Weather Data ◽  
Geographic Factors ◽  
Explanatory Variables ◽  
Total Percentage ◽  
Forest Fire Management ◽  
Mediterranean Countries ◽  
Daily Weather Data ◽  
Fire Loads

Human-caused forest fires are common in Mediterranean countries. Forest fire management agencies customarily estimate daily fire loads by using meteorological fire danger rating indices, based on variables registered daily by weather stations. This paper is focussed on the evaluation of the relative performance of a comprehensive set of commonly used fire weather indices by developing holistic daily fire occurrence models in Spain involving also other topographic, fuel and human-related geographic factors. The data consisted of historical records of daily fire occurrences, daily weather data and geographic characteristics for the peninsular territory of Spain in a 10-km-spatial resolution grid, for the period from 2002 to 2005. The prediction units were 10 × 10-km-grid cells but in order to take into account the spatial variation in relationships between explanatory variables and historical occurrences, Spain was divided into 53 ecoregions and a logistic regression model was developed for each one of these regions. The explanatory variables included in the models illustrated which weather and geographic factors primarily affected daily human-caused fires in the ecoregions. The validation of the estimated ignition probabilities with the fire occurrences registered during 2005, reserved for independently testing the model’s predictive capability, resulted in values of total percentage correctly predicted varying from 47.4 to 82.6%.

Weather, herbage quality and milk production in pastoral systems. 1. Temporal patterns and intra-relationships in weather variables

2009 ◽  
Vol 49 (3) ◽  
pp. 192 ◽  
Author(s):  
J. R. Roche ◽  
L. R. Turner ◽  
J. M. Lee ◽  
D. C. Edmeades ◽  
D. J. Donaghy ◽  
...  
Keyword(s):  
Potential Evapotranspiration ◽  
Temporal Trends ◽  
Animal Production ◽  
Weather Data ◽  
Weather Variables ◽  
Weather Factors ◽  
Pastoral Systems ◽  
Substantial Impact ◽  
Production Region ◽  
Daily Weather Data

Prevailing weather conditions are one factor that influences herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, herbage growth and quality, and animal production, it is beneficial to first quantify temporal trends in weather variables. The objective of the present study was to investigate the existence of temporal weather trends in a predominantly dairy production region of New Zealand, and to quantify the level of intra-dependency among the weather variables measured. Daily weather data across the years 1995 to 2001 were merged. Fitted sinusoidal functions demonstrated cyclic temporal trends in weather throughout the year. Air and soil temperatures, radiation, and potential evapotranspiration were highly repeatable within fortnight. Repeatability of all other weather variables was low; for example repeatability of rainfall was ≤7%. Linear relationships were also observed among all weather variables. All air and soil temperature measurements were highly positively correlated with each other (r = 0.53–0.99), and with evaporation (r = 0.40–0.68) and potential evapotranspiration (r = 0.43–0.79), while maximum air temperature was positively correlated with radiation (r = 0.61). Further investigation is required to quantify the effect of temporal weather trends on herbage growth and quality, and subsequent animal production.

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