14:00 〜 14:15
[MIS05-14] Frequency of dangerous hydrometeorological events impacting forest ecosystems in different biomes
★Invited Papers
キーワード：forest ecosystems, dangerous hydrometeorological events, climate risks, frequency of hazards
Natural systems (ecosystems, species, populations) are subject to dangerous and unfavorable hydrometeorological phenomena in accordance with their geographical location. The diversity of forest ecosystems in Northern Eurasia is large and includes boreal coniferous forests at the boundary of tundra, mixed coniferous-broadleaved forests, temperate broadleaved forests at the boundary of primary grasslands (steppes) and wet and dry subtropical forests. Totally 49 forest biomes have been identified in the territory of Russia using a bioclimatic classification.
The sensitivity to a dangerous phenomenon of a certain intensity in various components of one natural system may vary from no influence to complete destruction. The degree of threat can be assessed by identifying threshold values, when exceeded, significant damage is caused to at least one of the components of the natural system in the form of large-scale destructive disturbances, irreversible changes or the death of a significant proportion of the population of living organisms. The mass death of trees is the most evident manifestation of the catastrophic level of hazardous impacts.
Data on recorded hazardous phenomena within the biomes were collected from 200 meteorological stations in forest biomes from Eastern Europe to Far East. Data on the hazards’ impacts on natural systems are summarized from about 100 scientific publications. We have identified two levels of threshold values: the first is the actual possibility of causing significant damage; the second means that consequences become catastrophic. Depending on the threshold value, the time for natural restoration of forest ecosystems and the proportion of irreversible consequences increases.
As a result, 17 dangerous phenomena have been observed in almost all forest biomes: strong wind, tornado, heavy rain, heavy snow, large hail, severe blizzard, severe dust (sand) storm, ice crust formation, extreme frost, abnormally cold weather, extreme heat, abnormally hot weather, extreme fire danger, dry winds (hot windy weather several days), atmospheric drought, high snow cover, floods (of various origins). Mudflows, landslides and avalanches are manifested only in mountainous regions.
The intensity of 8 hazardous phenomena reached the first threshold value in all 49 forest biomes in Russia: strong wind, heavy rain, abnormally cold and abnormally hot weather, atmospheric drought, extreme fire danger, ice crust and floods. Of these, only abnormally hot and abnormally cold weather reach the second threshold in all biomes. The fewest biomes (9) are affected by severe sandstorms.
7 hazardous phenomena reached the second threshold in more than 90%: strong wind, abnormally cold and abnormally hot weather, extreme fire danger, dry wind, ice crust, flood and two phenomena never reached it: extreme heat and atmospheric drought. Mudflows and avalanches can be extremely strong in all regions, where they are possible – almost 50% of biomes. Huge landslides spread is broader – 67% of biomes, including sea shores and high river banks at plain areas.
The frequency of any event may vary from annual to never observed. Even within one forest biome an event may be observed different times at different weather station for the same period. Generally, in boreal forests strong wind, blizzard, abnormally cold weather and high snow cover of the first may be observed threshold may be observed every year and reach the second threshold from every year to less than in 50 years. Extreme heat, dry winds and atmospheric drought happen one time in 10 years or less. Heavy rain and snow vary from every year to one time in 50 years depending of seasonal precipitation maximum.
In mixed coniferous-broadleaved forests all dangerous hydrometeorological events, connected to temperature and precipitation extremes, strong winds have been observed as minimum one time in 10 years or more. In temperate broadleaved and subtropical forests heat extremal events happen in 2-3 times more often, than cold. Heavy rain reaches the second threshold every 5-10 years in subtropical forests and broadleaved and boreal forests near Pacific Ocean and Lake Baikal.
The frequency of dangerous hydrometeorological events significantly changes a picture of climate risks in forest biomes. A combination of high intensity (as minimum the first threshold is reached) and high frequency (every 5-10 years and more) mark the main risks and directions of climate change adaptation, as for natural forest restoration we need decades.
The main types of biomes are presented in the picture.
The sensitivity to a dangerous phenomenon of a certain intensity in various components of one natural system may vary from no influence to complete destruction. The degree of threat can be assessed by identifying threshold values, when exceeded, significant damage is caused to at least one of the components of the natural system in the form of large-scale destructive disturbances, irreversible changes or the death of a significant proportion of the population of living organisms. The mass death of trees is the most evident manifestation of the catastrophic level of hazardous impacts.
Data on recorded hazardous phenomena within the biomes were collected from 200 meteorological stations in forest biomes from Eastern Europe to Far East. Data on the hazards’ impacts on natural systems are summarized from about 100 scientific publications. We have identified two levels of threshold values: the first is the actual possibility of causing significant damage; the second means that consequences become catastrophic. Depending on the threshold value, the time for natural restoration of forest ecosystems and the proportion of irreversible consequences increases.
As a result, 17 dangerous phenomena have been observed in almost all forest biomes: strong wind, tornado, heavy rain, heavy snow, large hail, severe blizzard, severe dust (sand) storm, ice crust formation, extreme frost, abnormally cold weather, extreme heat, abnormally hot weather, extreme fire danger, dry winds (hot windy weather several days), atmospheric drought, high snow cover, floods (of various origins). Mudflows, landslides and avalanches are manifested only in mountainous regions.
The intensity of 8 hazardous phenomena reached the first threshold value in all 49 forest biomes in Russia: strong wind, heavy rain, abnormally cold and abnormally hot weather, atmospheric drought, extreme fire danger, ice crust and floods. Of these, only abnormally hot and abnormally cold weather reach the second threshold in all biomes. The fewest biomes (9) are affected by severe sandstorms.
7 hazardous phenomena reached the second threshold in more than 90%: strong wind, abnormally cold and abnormally hot weather, extreme fire danger, dry wind, ice crust, flood and two phenomena never reached it: extreme heat and atmospheric drought. Mudflows and avalanches can be extremely strong in all regions, where they are possible – almost 50% of biomes. Huge landslides spread is broader – 67% of biomes, including sea shores and high river banks at plain areas.
The frequency of any event may vary from annual to never observed. Even within one forest biome an event may be observed different times at different weather station for the same period. Generally, in boreal forests strong wind, blizzard, abnormally cold weather and high snow cover of the first may be observed threshold may be observed every year and reach the second threshold from every year to less than in 50 years. Extreme heat, dry winds and atmospheric drought happen one time in 10 years or less. Heavy rain and snow vary from every year to one time in 50 years depending of seasonal precipitation maximum.
In mixed coniferous-broadleaved forests all dangerous hydrometeorological events, connected to temperature and precipitation extremes, strong winds have been observed as minimum one time in 10 years or more. In temperate broadleaved and subtropical forests heat extremal events happen in 2-3 times more often, than cold. Heavy rain reaches the second threshold every 5-10 years in subtropical forests and broadleaved and boreal forests near Pacific Ocean and Lake Baikal.
The frequency of dangerous hydrometeorological events significantly changes a picture of climate risks in forest biomes. A combination of high intensity (as minimum the first threshold is reached) and high frequency (every 5-10 years and more) mark the main risks and directions of climate change adaptation, as for natural forest restoration we need decades.
The main types of biomes are presented in the picture.