9+ Essential Snow Properties & Effects

snow properties

9+ Essential Snow Properties & Effects

The traits of frozen precipitation, together with density, albedo, thermal conductivity, and liquid water content material, range considerably relying on meteorological circumstances throughout formation and subsequent metamorphism. For instance, freshly fallen, low-density snow can have a excessive albedo, reflecting a big portion of incoming photo voltaic radiation, whereas denser, older snow with a decrease albedo absorbs extra radiation, influencing snowpack evolution and soften charges.

Understanding the multifaceted nature of those traits is prime for numerous fields. Correct predictions of snowmelt runoff are essential for water useful resource administration and flood forecasting. Analyzing these traits can be important for avalanche forecasting and mitigation, winter highway upkeep, and ecological research analyzing the insulating properties of snow cowl for subnivian life. Traditionally, observations of those attributes have been integral to conventional ecological data in snow-dependent cultures.

This text delves additional into particular features, exploring the formation processes, measurement methods, and the influence of fixing local weather circumstances on the evolution of frozen precipitation traits.

1. Density

Density, a vital bodily property of snow, signifies the mass of snow per unit quantity, sometimes expressed in kilograms per cubic meter (kg/m). It represents a key indicator of snowpack circumstances and influences varied different snow properties. Density varies considerably relying on components akin to snow sort, temperature, wind, and age. Freshly fallen, powdery snow displays low densities, typically round 50-100 kg/m, whereas compacted or moist snow can attain densities exceeding 500 kg/m. This variability considerably impacts the snowpack’s bodily habits and its interplay with the encircling setting.

The density of a snowpack influences its thermal conductivity, stability, and water equal. A denser snowpack conducts warmth extra effectively, resulting in quicker soften charges in comparison with a much less dense snowpack. Greater density additionally contributes to elevated snowpack stability, lowering the chance of avalanches. Moreover, density is important for calculating snow water equal (SWE), a vital parameter for water useful resource administration. For instance, a deep snowpack with low density might need a decrease SWE than a shallower, denser snowpack. Understanding density variations inside a snowpack permits for extra correct estimations of SWE and higher predictions of spring runoff.

Correct measurement and evaluation of snow density are basic for quite a few purposes. Avalanche forecasting depends closely on density profiles to evaluate snowpack stability. Hydrological fashions make the most of density information to foretell snowmelt runoff and handle water assets successfully. Furthermore, local weather research incorporate snow density measurements to grasp the influence of fixing local weather circumstances on snowpack dynamics and the cryosphere. The challenges related to precisely measuring and modeling snow density in advanced terrains spotlight the continuing want for improved measurement methods and complex modeling approaches.

2. Snow Albedo

Snow albedo, the proportion of incoming photo voltaic radiation mirrored by the snow floor, represents a vital snow property influencing vitality stability and soften charges. Starting from close to 0 to 1, albedo dictates the quantity of photo voltaic vitality absorbed by the snowpack. Excessive albedo values point out excessive reflectivity, minimizing absorption, whereas low values signify higher absorption, accelerating soften. Understanding albedo variations is important for predicting snowpack evolution and its influence on hydrological cycles and local weather programs.

  • Components Influencing Albedo

    A number of components affect snow albedo, together with grain measurement, impurities, photo voltaic angle, and snowpack age. Contemporary snow with small, angular grains tends to exhibit excessive albedo because of a number of reflections throughout the snowpack. Impurities akin to mud, soot, and algae darken the snow floor, lowering albedo and rising photo voltaic absorption. Modifications in photo voltaic angle all through the day and seasons additionally have an effect on albedo, with decrease angles resulting in higher reflection. As snow ages, metamorphism alters grain measurement and form, usually reducing albedo.

  • Affect on Power Steadiness

    Snow albedo performs a vital position in regional and international vitality budgets. Excessive-albedo snow surfaces replicate a good portion of incoming photo voltaic radiation again into the ambiance, cooling the floor and influencing atmospheric circulation patterns. Conversely, decreased albedo because of melting or impurities will increase photo voltaic vitality absorption, accelerating snowmelt and warming the encircling setting. These suggestions mechanisms are important for understanding local weather change impacts on snow cowl and the cryosphere.

  • Measurement and Modeling

    Snow albedo measurements are obtained utilizing varied devices, together with pyranometers and spectroradiometers. Discipline measurements present helpful information for validating distant sensing methods that estimate albedo over bigger areas. Subtle fashions incorporate albedo information to simulate snowpack evolution, predict soften charges, and assess the influence of land cowl modifications on snow cowl dynamics. Correct albedo measurements are essential for enhancing the predictive capabilities of those fashions.

  • Local weather Change Implications

    Local weather change considerably impacts snow albedo by means of altered precipitation patterns, elevated temperatures, and modifications in impurity deposition. Hotter temperatures speed up snowmelt, lowering snow cowl period and exposing darker underlying surfaces, additional reducing albedo and amplifying warming. Modifications in precipitation patterns can affect snowpack thickness and density, not directly affecting albedo. Elevated deposition of light-absorbing impurities, akin to black carbon from wildfires, additional contributes to albedo discount and accelerated snowmelt.

Snow albedo, as a vital snow property, exerts appreciable affect on the interactions between the cryosphere and the broader local weather system. Understanding its advanced relationships with different snow traits and environmental components is important for precisely predicting snowpack dynamics, assessing water assets, and mitigating the impacts of local weather change on snow-dependent ecosystems.

3. Thermal Conductivity

Thermal conductivity, the speed at which warmth transfers by means of snow, represents a vital snow property influencing snowpack evolution, soften dynamics, and floor thermal regimes. Understanding its controlling components and variability is essential for predicting snowmelt runoff, assessing floor frost penetration, and understanding the thermal insulation supplied to subnivian ecosystems. This property, expressed in watts per meter-kelvin (W/mK), varies considerably relying on snow traits and environmental circumstances.

  • Density Dependence

    Snow density exerts a major affect on thermal conductivity. Denser snow, with higher ice-to-air ratio, facilitates extra environment friendly warmth switch in comparison with much less dense snow. As snow densifies by means of compaction and metamorphism, its thermal conductivity will increase, accelerating warmth switch throughout the snowpack and between the snow and the underlying floor. This relationship performs a vital position in predicting the timing and charge of snowmelt.

  • Affect of Grain Measurement and Form

    Snow microstructure, particularly grain measurement and form, additionally impacts thermal conductivity. Bigger, rounded grains facilitate warmth switch extra successfully than smaller, angular grains. Metamorphism processes that alter grain traits over time affect the snowpack’s thermal conductivity. These microstructural modifications contribute to the advanced temporal evolution of snowpack thermal properties.

  • Affect of Liquid Water Content material

    The presence of liquid water throughout the snowpack considerably enhances thermal conductivity. Water, with its increased thermal conductivity in comparison with ice and air, creates preferential pathways for warmth circulation. Even small quantities of liquid water can considerably enhance the general thermal conductivity of the snowpack, accelerating soften processes and influencing vitality trade with the ambiance and floor.

  • Temperature Results

    Temperature gradients throughout the snowpack drive warmth circulation and affect thermal conductivity. Steeper temperature gradients between the snow floor and the bottom promote higher warmth switch. Modifications in air temperature have an effect on snowpack temperature profiles and might affect the speed of metamorphism, not directly affecting thermal conductivity by means of modifications in snow density and grain traits.

These interconnected components spotlight the complexity of thermal conductivity inside snowpacks. Correct illustration of this property in snow fashions is important for predicting snowmelt runoff, assessing the impacts of local weather change on snow cowl, and understanding the thermal dynamics of snow-covered landscapes. The interaction of those components determines the snowpack’s thermal properties and its position in modulating vitality trade between the ambiance, floor, and subnivian ecosystems.

4. Liquid Water Content material

Liquid water content material, the fraction of liquid water current throughout the snowpack, considerably influences varied snow properties and performs a vital position in snowpack evolution and soften dynamics. Expressed as a proportion of the overall snow quantity, it impacts thermal conductivity, density, albedo, and mechanical power. The presence of liquid water, even in small portions, can dramatically alter the snowpack’s bodily and thermal habits.

The first supply of liquid water in snow is soften from photo voltaic radiation, heat air temperatures, or rainfall. Liquid water may also be generated throughout the snowpack by means of inside processes like section modifications and temperature gradients. The quantity of liquid water current is dependent upon components akin to meteorological circumstances, snowpack properties (e.g., density, grain measurement), and topography. For instance, a dense snowpack with giant grains retains extra liquid water than a unfastened, low-density snowpack. The distribution of liquid water throughout the snowpack is not uniform; it tends to build up in layers or preferential circulation paths, influenced by snowpack stratigraphy and permeability.

Elevated liquid water content material enhances thermal conductivity, accelerating warmth switch throughout the snowpack and between the snow and the bottom. This accelerated warmth switch can set off additional melting and affect floor thermal regimes. Greater liquid water content material additionally contributes to elevated snow density because the water fills air areas between snow grains. The presence of liquid water can lower snow albedo by lowering the quantity of mirrored photo voltaic radiation, resulting in elevated absorption and additional soften. Mechanically, increased liquid water content material weakens the snowpack, rising the danger of avalanches in mountainous areas. Understanding liquid water content material dynamics is essential for correct snowmelt forecasting, water useful resource administration, and avalanche prediction. Moreover, it performs a big position in ecological research analyzing the influence of snowmelt timing on subnivian ecosystems and vegetation development.

5. Grain measurement and form

Snow grain measurement and form, basic elements of snow microstructure, considerably affect macroscopic snow properties and habits. These microscopic traits, evolving by means of meteorological and bodily processes, have an effect on the snowpack’s density, thermal conductivity, albedo, and mechanical power. Understanding this interaction between microstructure and macroscopic properties is essential for predicting snowpack evolution, soften dynamics, and avalanche formation.

Initially, snowflakes exhibit advanced, dendritic constructions. Subsequent metamorphism, pushed by temperature gradients and vapor stress variations throughout the snowpack, transforms these intricate shapes into easier, rounded grains. This transformation will increase snow density because the air areas between grains lower. Bigger, rounded grains facilitate extra environment friendly warmth switch, rising thermal conductivity and accelerating soften charges. Conversely, smaller, angular grains entice extra air, lowering density and thermal conductivity. Grain form additionally impacts albedo; faceted crystals with a number of reflecting surfaces enhance albedo, whereas rounded grains are inclined to lower it. The scale and form of snow grains affect the snowpack’s mechanical power, with bigger, rounded grains contributing to weaker layers liable to slab avalanche formation.

Sensible implications of understanding grain measurement and form are quite a few. Avalanche forecasting depends closely on analyzing snowpack stratigraphy and figuring out weak layers characterised by particular grain sorts. Hydrological fashions incorporate grain measurement data to foretell snowmelt runoff precisely. Local weather research make the most of snow microstructure information to grasp the influence of fixing temperature and precipitation patterns on snowpack evolution. Additional analysis into the advanced interaction between grain traits and macroscopic snow properties is important for refining predictive fashions and mitigating the impacts of local weather change on snow-dependent ecosystems.

6. Snow Depth

Snow depth, a readily observable attribute, represents the vertical extent of amassed snow cowl. Whereas seemingly easy, its relationship with different snow properties is advanced and essential for understanding snowpack dynamics. Snow depth influences and is influenced by components akin to snowfall accumulation, compaction, melting, and wind redistribution. Its measurement offers important data for varied purposes, from water useful resource administration to avalanche forecasting.

  • Spatial Variability

    Snow depth displays important spatial variability because of terrain options, wind patterns, and vegetation cowl. Mountainous areas typically expertise substantial variations in snow depth because of wind drifting and preferential deposition on lee slopes. Sheltered areas, akin to forests, can accumulate deeper snowpacks in comparison with uncovered ridges. Understanding this spatial variability is vital for correct assessments of snow water equal and for predicting localized soften patterns.

  • Temporal Dynamics

    Snow depth modifications dynamically all through the winter season. Accumulation from snowfall occasions will increase snow depth, whereas compaction and metamorphism cut back it even with out soften. Melting occasions can quickly lower snow depth, significantly throughout spring. Analyzing temporal modifications in snow depth offers helpful insights into snowpack evolution, soften charges, and the general water stability of a area.

  • Affect on Snow Properties

    Snow depth influences different snow properties, together with density, thermal conductivity, and albedo. Deep snowpacks can exhibit increased densities on the base because of compaction from the overlying snow. The depth of the snowpack influences temperature gradients, impacting thermal conductivity and soften charges. Moreover, snow depth can not directly have an effect on albedo, significantly in areas with patchy snow cowl, the place uncovered floor influences total reflectivity.

  • Measurement Methods

    A number of methods measure snow depth, starting from handbook snow probes to distant sensing strategies. Handbook measurements present point-specific information, whereas distant sensing applied sciences, akin to LiDAR and radar, provide spatially in depth data. The selection of methodology is dependent upon the dimensions of the research and the specified accuracy. Correct snow depth measurements are essential for calibrating hydrological fashions, validating distant sensing information, and informing water useful resource administration choices.

Snow depth, whereas a basic measurement, offers a gateway to understanding the extra advanced interaction of snow properties. Its variability in area and time displays the dynamic nature of snowpack processes, influencing soften charges, water assets, and ecosystem dynamics. By integrating snow depth information with different snow property measurements, a complete understanding of the cryosphere and its position within the Earth’s local weather system emerges.

7. Hardness

Snow hardness, a measure of snow resistance to penetration, offers essential insights into snowpack stability and metamorphism. This property, influenced by density, temperature, and grain traits, immediately pertains to avalanche forecasting, backcountry journey security, and the general mechanical habits of the snowpack. Understanding its variability and contributing components is important for decoding snowpack circumstances and predicting potential hazards.

  • Measurement Methods

    Varied strategies assess snow hardness, starting from easy hand exams to quantitative devices. Hand exams, whereas subjective, present fast subject assessments. Instrumented measurements, such because the rammsonde, provide extra exact and goal information. The selection of methodology is dependent upon the precise software and required stage of element.

  • Relationship with Density and Grain Traits

    Snow hardness correlates strongly with density and grain traits. Denser snow with well-bonded, rounded grains displays higher hardness. Conversely, low-density snow with poorly bonded, angular grains displays decrease hardness. This relationship highlights the interaction between microstructure and macroscopic mechanical properties.

  • Affect of Temperature

    Temperature considerably influences snow hardness. Hotter temperatures close to the melting level lower hardness, because the bonds between snow grains weaken. Colder temperatures enhance hardness, selling stronger intergranular bonds. Diurnal temperature fluctuations can create variations in hardness throughout the snowpack, contributing to instability.

  • Implications for Avalanche Forecasting

    Snow hardness performs an important position in avalanche forecasting. Weak layers throughout the snowpack, characterised by low hardness, can act as potential failure planes for slab avalanches. Assessing hardness profiles helps establish these weak layers and consider snowpack stability. This data is vital for backcountry journey choices and avalanche mitigation methods.

Snow hardness, inextricably linked to different snow properties, offers vital insights into the mechanical habits and stability of the snowpack. Its variability, pushed by components akin to density, temperature, and grain traits, underlines the advanced nature of snow metamorphism and its implications for avalanche forecasting and secure backcountry journey. Understanding these interrelationships is important for mitigating dangers and selling knowledgeable decision-making in snow-covered environments.

8. Layer Stratigraphy

Snowpack stratigraphy, the layered construction of a snowpack, displays the historical past of particular person snowfall occasions and subsequent metamorphic processes. Every layer possesses distinct properties density, hardness, grain measurement and form, temperature, and liquid water content material decided by the meteorological circumstances prevalent throughout its deposition and subsequent evolution. Analyzing layer stratigraphy offers essential insights into snowpack stability, meltwater dynamics, and previous climate patterns. For example, a layer of weak, faceted crystals buried beneath a cohesive slab of denser snow presents a big avalanche hazard. Understanding the properties of every layer and their interrelationships is important for correct avalanche forecasting.

The temporal evolution of snowpack stratigraphy is a posh interaction of deposition, metamorphism, and melt-freeze cycles. Contemporary snowfall types distinct layers, typically with low density and excessive albedo. Subsequent temperature gradients throughout the snowpack drive metamorphism, altering grain measurement and form, and influencing layer properties. Soften-freeze cycles additional consolidate the snowpack, rising density and forming ice lenses. These processes create a stratified snowpack with various bodily and mechanical properties, recorded within the stratigraphy. For instance, a sustained interval of clear, chilly climate can result in the formation of depth hoar, a weak layer of huge, faceted crystals close to the bottom. This layer’s presence considerably influences the snowpack’s total stability and might contribute to persistent weak layer issues all through the winter season.

Analyzing snowpack stratigraphy is prime for understanding snowpack stability and predicting potential hazards. Snow pit evaluation, an ordinary approach in avalanche forecasting, includes analyzing the layers inside a snowpack, documenting their properties, and assessing their potential to fail. Understanding the cause-and-effect relationships between meteorological circumstances, metamorphic processes, and ensuing layer properties is paramount for correct avalanche danger evaluation. Moreover, snowpack stratigraphy informs hydrological fashions, offering insights into meltwater pathways and the timing of spring runoff. Challenges in precisely modeling the advanced processes influencing stratigraphy spotlight the continuing want for improved measurement methods and mannequin growth. Finally, an intensive understanding of snowpack stratigraphy offers essential insights into the dynamic nature of the cryosphere and its interplay with the broader setting.

9. Impurities (e.g., mud)

Impurities inside snow, akin to mud, soot, black carbon, and natural matter, exert a big affect on snow properties and play a vital position in snowpack evolution and soften dynamics. These impurities, originating from varied sources together with atmospheric deposition, industrial emissions, and wildfires, alter the optical and thermal properties of snow, resulting in cascading results on the cryosphere and broader local weather system. The presence of impurities decreases snow albedo, rising the absorption of photo voltaic radiation and accelerating soften charges. This phenomenon is especially pronounced in areas experiencing excessive mud deposition, such because the Himalayas and the Arctic, the place snowmelt contributes considerably to water assets.

The influence of impurities on snow albedo is dependent upon their focus, measurement, and optical properties. Darker impurities, like black carbon, take up extra photo voltaic radiation than lighter-colored mud particles. Greater concentrations of impurities result in a higher discount in albedo and accelerated soften. This impact is amplified by optimistic suggestions mechanisms: because the snow floor melts, impurities turn out to be extra focused on the remaining snow, additional reducing albedo and accelerating soften. This phenomenon contributes to earlier snowmelt and decreased snow cowl period, impacting water useful resource availability and ecosystem dynamics. For instance, mud deposition on Himalayan glaciers accelerates melting, influencing downstream river flows and impacting agricultural practices in downstream areas. Equally, black carbon deposition within the Arctic contributes to sea ice soften, impacting international sea ranges and altering ocean circulation patterns.

Understanding the advanced interactions between impurities and snow properties is essential for precisely predicting snowpack evolution, assessing water useful resource availability, and mitigating the impacts of local weather change. Challenges stay in quantifying the sources and transport of impurities, precisely measuring their influence on snow albedo, and incorporating these processes into predictive fashions. Addressing these challenges requires interdisciplinary analysis efforts combining subject measurements, distant sensing methods, and complex modeling approaches. The sensible implications of this understanding are far-reaching, informing methods for air air pollution management, water useful resource administration, and local weather change mitigation. The interaction between impurities and snow properties underscores the interconnectedness of atmospheric processes, the cryosphere, and the broader Earth system.

Steadily Requested Questions on Snow Properties

This part addresses widespread inquiries relating to the traits of snow and their significance.

Query 1: How does snow density have an effect on avalanche danger?

Greater density snowpacks are usually extra secure than low-density snowpacks. Nonetheless, important density variations between layers inside a snowpack can create unstable circumstances. A dense slab overlying a weak, low-density layer can result in slab avalanches.

Query 2: Why is snow albedo vital for local weather change research?

Snow albedo influences the Earth’s vitality stability. Excessive albedo displays photo voltaic radiation again into area, cooling the planet. Lowering snow cowl because of local weather change reduces this reflective floor, resulting in elevated absorption of photo voltaic radiation and additional warming, making a optimistic suggestions loop.

Query 3: How does liquid water content material have an effect on snowmelt runoff predictions?

Liquid water content material influences the speed of snowmelt. Greater liquid water content material will increase thermal conductivity, accelerating soften and contributing to earlier and doubtlessly extra fast runoff. Correct measurements of liquid water content material are essential for predicting runoff timing and magnitude.

Query 4: What’s the significance of snow stratigraphy for avalanche security?

Snow stratigraphy reveals the layering inside a snowpack, together with weak layers that could be liable to failure. Analyzing these layers helps assess snowpack stability and predict potential avalanche hazards. This data is essential for backcountry journey choices and avalanche mitigation methods.

Query 5: How do impurities in snow have an effect on soften charges?

Impurities like mud and black carbon lower snow albedo, resulting in elevated absorption of photo voltaic radiation. This elevated absorption accelerates snowmelt and contributes to earlier snow disappearance, impacting water assets and ecosystem dynamics.

Query 6: Why is knowing snow thermal conductivity vital for ecological research?

Snow thermal conductivity influences floor temperatures and the insulation supplied to subnivian ecosystems. This insulation impacts the survival of crops and animals dwelling beneath the snow. Modifications in snow properties because of local weather change can alter this insulation, impacting subnivian life.

Understanding these basic snow properties is essential for managing water assets, predicting pure hazards, and comprehending the advanced interaction between the cryosphere and the broader setting.

The next sections will delve deeper into particular measurement methods and the influence of fixing local weather circumstances on snow properties.

Sensible Purposes and Concerns

This part offers sensible steering associated to frozen precipitation traits, emphasizing their relevance throughout varied disciplines.

Tip 1: Correct Density Measurements for Water Useful resource Administration:

Exact density measurements are basic for calculating snow water equal (SWE), a vital parameter for predicting spring runoff and managing water assets successfully. Using acceptable measurement methods, akin to snow coring and gamma-ray attenuation, ensures dependable SWE estimations.

Tip 2: Albedo Monitoring for Local weather Change Research:

Monitoring albedo modifications over time offers helpful insights into the impacts of local weather change on snow cowl. Combining subject measurements with distant sensing methods permits for complete assessments of albedo variations and their affect on vitality stability.

Tip 3: Thermal Conductivity Concerns for Infrastructure Design:

Understanding snow thermal conductivity is important for designing infrastructure in snow-prone areas. Correct insulation and floor preparation can mitigate the consequences of frost heave and guarantee structural integrity.

Tip 4: Evaluating Liquid Water Content material for Avalanche Forecasting:

Monitoring liquid water content material throughout the snowpack helps assess avalanche danger. Elevated liquid water content material can weaken snowpack layers, rising the chance of moist snow avalanches. Incorporating liquid water content material measurements enhances avalanche forecasting accuracy.

Tip 5: Deciphering Snow Stratigraphy for Backcountry Security:

Analyzing snow stratigraphy allows backcountry vacationers to establish potential weak layers throughout the snowpack. This information facilitates knowledgeable decision-making relating to route choice and avalanche danger evaluation.

Tip 6: Mitigating the Affect of Impurities on Snowmelt:

Implementing measures to scale back impurity deposition, akin to controlling industrial emissions and mitigating wildfire impacts, might help protect snow albedo and preserve snow cowl period. These efforts contribute to sustainable water useful resource administration and mitigate local weather change impacts.

Tip 7: Integrating Snow Properties Knowledge into Predictive Fashions:

Integrating complete snow property information into hydrological and local weather fashions enhances predictive capabilities. This integration results in extra correct forecasts of snowmelt runoff, improved water useful resource administration methods, and a greater understanding of local weather change impacts on snow-covered areas.

By contemplating these sensible purposes, researchers, practitioners, and policymakers can make the most of data of snow traits to make knowledgeable choices relating to water useful resource administration, infrastructure growth, and local weather change adaptation methods.

The concluding part will synthesize key findings and emphasize future analysis instructions within the subject of snow science.

Conclusion

Traits of snow, encompassing density, albedo, thermal conductivity, liquid water content material, grain measurement and form, snow depth, hardness, layer stratigraphy, and impurities, exert a profound affect on numerous environmental processes. Their intricate interrelationships govern snowpack evolution, soften dynamics, avalanche formation, and the broader hydrological cycle. Understanding these properties is paramount for correct predictions of snowmelt runoff, efficient water useful resource administration, and knowledgeable avalanche hazard mitigation. Moreover, these traits play a vital position in modulating vitality trade between the cryosphere and the ambiance, influencing regional and international local weather patterns.

Continued analysis into the advanced interaction of snow properties stays important for refining predictive fashions, enhancing mitigation methods, and adapting to the impacts of local weather change on snow-covered areas. Advances in measurement methods, distant sensing applied sciences, and built-in modeling approaches will additional elucidate the intricate dynamics of the cryosphere and its essential position within the Earth’s local weather system. This information empowers knowledgeable decision-making relating to water useful resource administration, ecosystem preservation, and sustainable growth in snow-dependent areas worldwide.