Microclimates

10 Key excerpts on "Microclimates"

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  Microclimate for Cultural Heritage

  • Dario Camuffo(Author)
  • 1998(Publication Date)
  • Elsevier Science

    (Publisher)

  In climate research, meteorology and physical geography, the distinction is rather clear and is determined by the field of interest, i.e. the 'global climate' refers to our planet, the 'regional climate' to a geographical homogeneous area, the 'local climate' to a small limited area like a mountain, a valley, a city. Similarly, for conservation, it is useful to use clear terms, derived from the above mentioned sciences, e.g. 'regional climate' for the main characteristics of the geographic area where the monument is found, 'urban', 'rural', 'mountain', 'valley', 'coastal' and so on for the next dimensional Step, and 'microclimate' relating to the small location, e.g. a corner of street, a square, a room, where the monument or the object is sited. This definition does not imply a precise size, but focuses the attention on a specific artefact (e.g. a historic building, a statue, a small exhibit) and its surrounding, so that the same term can also apply when studying the interactions between a portion of a monument and the air nearby. In practice, it refers to the whole ambient which is necessary to study in order to know the factors which have a direct influence on the physical state of the monument and the interactions with the air and the surrounding objects. Now that the prefix 'micro' has been explained, it might be useful to clarify also the word 'climate'. The following definitions can be found: 'climate is the synthesis of the day-to-day weather conditions in a given area', 'climate is the statistical description of weather and atmospheric conditions as exhibited by the patterns of such conditions, in a given region, over a specified period of time long enough to be representative (usually a number of decades)', 'climate is the fluctuating aggregate of atmospheric conditions characterised by the states and developments of weather in a given area' (Maunder, 1994).

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  Historical Ecology

  Learning from the Past to Understand the Present and Forecast the Future of Ecosystems

  • Guillaume Decocq(Author)
  • 2022(Publication Date)
  • Wiley-ISTE

    (Publisher)

  Forest edges have a very contrasting microclimate compared to forest interiors with, for example, higher air and soil temperatures, lower soil moisture, higher light availability and higher wind speed compared to forest interiors. These microclimatic conditions are induced by the exposed character of forest edges, and also by their altered vegetation structure. As a result, forest edges harbor distinct communities of plants, vertebrates, arthropods and microbes. Forest Microclimates are increasingly altered through edge effects since forest fragmentation and hence edge creation is a still ongoing process. Based on forest edge research, we can assume that microclimate temperatures in forest patches have increased in the past due to the increasing proportion of edges compared to interior forest. The forest microclimate is not only affected by plot and stand characteristics, but also by the landscape in which it is embedded. Several characteristics of the surrounding landscape influence the forest microclimate, either in a direct or indirect way. Topography is one of the most determining factors of a landscape and can have a strong impact on the microclimate, but does not change strongly over time. The same applies to the presence and size of large water bodies. However, other landscape features are of a dynamic nature and these are of prime importance to estimate how historical (and future) Microclimates at the landscape-scale differ from today (Table 20.1). Microclimatic buffering is related to the macroclimate, a feature changing on an even larger scale than the landscape scale. Increasing ambient air temperatures due to macroclimate change might lead to increased buffering of maximum temperatures in forests. Furthermore, regional hydrological conditions and varying levels of soil moisture can affect microclimatic buffering through the evapotranspiration and the transformation of sensible to latent heat.

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  Agriculture in Dry Lands

  Principles and Practice

  • I. Arnon(Author)
  • 2012(Publication Date)
  • Elsevier Science

    (Publisher)

  Microclimate at plant level The microclimate just above a crop and under its canopy (eco-climate) is influenced by the particular type of crop, and may be strikingly different from the climate of the surrounding environment. Even emerging seedlings will alter the climate near the soil surface, by reducing air movement and by shading the ground. As the plants grow, the extremes in temperatures of the soil surface are reduced; even so, the range of temperatures at the soil surface may be double that of the temperatures recorded in the standard meteorological screen. The eco-climate may be more humid and cooler than the atmosphere above the crop, which circumstances may create favourable conditions for the spread of certain diseases. Leaf temperatures in the sunlight may be higher than the air temperature by day and lower than the air temperature by night. The intensity and quality of light change as the rays pass through the plant canopy. Heat advection Irrigated areas are usually isolated islands of above-normal moisture conditions, enclosed in a vast expanse of dryland. If warm air, from surrounding dry areas, passes over a cooler and moister irrigated area, the microclimate of the latter at plant Microclimate 77 level will be influenced up to a down-wind distance of 80 to 100 m. This influence usually consists of the advection of sensible heat (Fritschen and Bavel, 1963) (the so-called oasis effect, Lemon et al., 1957). Advection has been defined as the ex-change of energy, moisture, or momentum due to horizontal heterogeneity (Philip, 1959). When the warm wind moves through a crop, it is cooled and supplies heat for evapotranspiration; this is known as the clothesline effect (Tanner, 1957). In dry regions, evapotranspiration may be increased significantly, through advec-tion of sensible heat (Fritschen and Bavel, 1963). In arid and subhumid climates, wind can contribute as much as half the energy consumed in evapotranspiration (Blad, 1983).

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  Environmental Control of Plant Growth

  • L.T. Evans(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  It appears to be common and extensive in aquatic plants (e.g. Harder, 1924), but much more limited in terrestrial plants (e.g. Björkman et al, 1960). A possible explanation of this dif-ference is that conditions in the microenvironments of land plants, and in the plants themselves, fluctuate too extremely for extensive tempera- 426 L. Τ. Evans ture acclimation to occur. In the more stable environments of aquatic plants, and possibly also in plants grown under controlled conditions, acclimation may be a more potent phenomenon, leading to relatively better performance under extreme conditions. We have seen that plants may respond even to the brief fluctuations in their natural environment, and that these responses may be either exaggerated, when overshoot occurs, or muted, when acclimation occurs. But we have, as yet, too little information to allow us to assess the rela-tive importance of the long-term climatic changes and of the short-term weather fluctuations for the growth of plants in the field. II. Spatial Diversity in Natural Microclimates In controlled environments, conditions are not only relatively stable with time but also relatively uniform spatially, with only slight vertical profiles, and at the rates of air circulation required for control the leaf temperature of many species is close to the air temperature. In the field, microclimatic conditions within the plant-air layer may be very different from those of the air around them. Thus, standard meteorological screen conditions, which are becoming of less importance in synoptic meteorology, are also of limited value in indicating plant conditions. Moreover, according to Sreenivasan and Ramabhadran (1950), who made a statistical study of the Microclimates of three tropi-cal crops in three seasons of the year, microclimatic conditions cannot be predicted from standard meteorological data. However, analog com-puters of the kind described by Halstead et al.

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  Applied Climatology

  Principles and Practice

  • Allen Perry, Dr Russell Thompson, Russell Thompson(Authors)
  • 2013(Publication Date)
  • Routledge

    (Publisher)

  PART 3: CLIMATE AND THE CULTURAL ENVIRONMENTS The following nine chapters examine the impact of climate on the development of the cultural environment, through its influence on human behavioural patterns (namely, comfort/health and social responses) and a wide range of human activities, including the built environment and a host of commercial-economic considerations. These include industrial operations, transport systems, agriculture, fisheries and forestry, recreation/tourism and fuel/power supplies. Once again, the issue of climate change is discussed by most authors (to varying degrees). 12 COMFORT, CLOTHING AND HEALTH Andris Auliciems INTRODUCTION: HUMAN ADAPTABILITY AND MICROCLIMATE MANAGEMENT In Part 2 of this book, the impacts of the past, current and predicted climates were discussed within the context of the functioning of the physical and biological environments. In this first chapter of Part 3, the impacts of climate on human comfort, clothing and health are considered. The proliferation of western lifestyles, clothing, technology in building construction and microclimate control have tended towards homogenizing atmospheric environments to which humans are exposed. Irrespective of market forces that drive these developments, in a global ecosystem increasingly threatened by environmental degradation and anthropogenic climate change, such specialization in adaptation needs to be examined in terms of (1) sustainability over the longer term, and (2) the human species overall ‘biological fitness’, or adaptability (Medwar, 1957)

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  City, Climate, and Architecture

  A Theory of Collective Practice

  • Sascha Roesler(Author)
  • 2022(Publication Date)
  • Birkhäuser

    (Publisher)

  Global Adaptations after 1945 164 5.1.3 Microclimatic Walks: Mobilizing the Body-Territory For a deliberate design of urban Microclimates, new collaborations must be established, rethinking “the Picturesque” as a man-made form of nature. 62 In the second half of the 20th century, landscape architects and architects aimed at reconciling the two aforemen- tioned perspectives—the aesthetics and thermody- namics of urban Microclimates—in a new understand- ing of microclimatic urban design. By reassessing the nature in the city, new accounts of the climate of cit- ies emerged. The overall goals of ecology and demo- cratic participation in urban development went along with new methodologies of how to explore and how to design the city as a green city, taking the perspec- tives of the residents into account. As part of those assessments, “the relation between urban morphology, microclimate, and thermal com- fort” was examined from the perspective of the us- er. 63 Vasilikou and Nikolopoulou speak of “the as- sessment of variations in the thermal sensation of users through ‘microclimatic walks’”, exploring the thermal qualities of the urban environment. 64 The main goal of these walks addressing “physical, psy- chological, and physiological” 65 aspects of microcli- mates was “to identify a specific change in the ther- mal conditions and define its quality”. 66 The methodologies included the “monitoring of microcli- matic conditions, field surveys with question- naire-guided interviews with the public, statistical analysis, evaluation of the environmental perfor- mance of urban textures, comfort mapping, social study of open spaces, and design guides and propos- als”. 67 Overall, the perspectives of experts and citi- zens were amalgamated in the microclimatic walks. 68 The pioneers, who examined the “intimate ground- level experience” 69 of the city with bodily–sensory means, are to be found in the 1960s in the fields of architecture and landscape architecture.

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  Heating, Cooling, Lighting

  Sustainable Design Methods for Architects

  • Norbert Lechner(Author)
  • 2014(Publication Date)
  • Wiley

    (Publisher)

  The various forces in the atmosphere interact to form a large set of diverse climates. Later in the chapter there will be a description of seventeen different climate regions found in the United States and Canada.

  5.3 MICROCLIMATE

  For a number of reasons, the local climate can be quite different from the climate region in which it is found. If buildings are to relate properly to their environment, they must be designed for the microclimate in which they exist. The following are the main factors responsible for making the microclimate deviate from the macroclimate:

  1. Elevation above sea level. The steeper the slope of the land, the faster the temperature will drop with an increase in elevation. The limit, of course, is a vertical ascent, which will produce a cooling rate of about 3.6°F (2°C) per 1000 ft (300 m).
  2. Form of land. South-facing slopes are much warmer than north-facing slopes because they receive much more solar radiation (Fig. 5.3a ). For this reason, ski slopes are usually found on the north slopes of mountains, while vineyards are located on the south slopes (Fig. 5.3b ). South slopes are also protected from the cold winter winds that usually come from the north. West slopes are warmer than east slopes because the period of high solar radiation coincides with the high ambient air temperatures of the afternoon. Low areas tend to collect pools of cold, heavy air (Fig. 5.3c ). If the air is also moist, fog will frequently form. The fog, in turn, reflects the solar radiation, so these areas remain cool longer in the morning.
     Figure 5.3a The north side (south slope) of this east–west road is several weeks further into spring than the south side (north slope), where the snow melts much more slowly.
     Figure 5.3b South-facing slopes can receive more than one hundred times as much solar radiation as north-facing slopes.
     Figure 5.3c

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  Mountain Geography

  Physical and Human Dimensions

  • Martin F. Price, Alton C. Byers, Donald A. Friend, Thomas Kohler, Larry W. Price, Martin F. Price, Alton C. Byers, Donald A. Friend, Thomas Kohler, Larry W. Price(Authors)
  • 2013(Publication Date)
  • University of California Press

    (Publisher)

  41 CHAPTER THREE Mountain Climate ANDREW J. BACH and LARRY W. PRICE Climate is the fundamental factor in establishing a natu-ral environment, setting the stage on which all physical, chemical, and biological processes operate. This becomes especially evident at the climatic margins of the Earth, namely desert and tundra. Under temperate conditions, the effects of climate are often muted and intermingled, so that the relationships between stimuli and reactions are difficult to isolate, but under extreme conditions such relationships become more evident. As extremes constitute the norm in many areas within high mountains, a basic knowledge of climatic processes and characteristics is key to understanding the mountain milieu. In mountain areas, great environmental contrasts occur within short distances as a result of the diverse topogra-phy and highly variable nature of the energy and mois-ture fluxes. While in the mountains, have you ever sought refuge from the wind in the lee of a rock? If so, you have experienced the kind of difference that can occur over a small distance. Near the margin of a species’ distribution, such differences may decide between life and death; thus, plants and animals reach their highest elevations by tak-ing advantage of microhabitats. Great variations also occur within short time spans. When the sun is shining, it may be quite warm, even in winter, but if a passing cloud blocks the sun, the temperature can drop rapidly. Therefore, areas exposed to the sun undergo much greater and more fre-quent temperature contrasts than those in shade. This is true for all environments, but the difference is much greater in mountains because the thin alpine air does not hold heat well and allows more solar radiation to reach the surface. More generally, the climate of a slope may be very dif-ferent from that of a ridge or valley.

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  Ethnobotany

  A Methods Manual

  • Gary J. Martin(Author)
  • 2010(Publication Date)
  • Routledge

    (Publisher)

  Climatologists set up weather stations in order to measure rainfall, temperature, evaporation and other aspects of the weather. Because they take records every day for many years, they are able to observe not only seasonal fluctuations but also variations from year to year. This information is generally available in the form of weather tables organized by locality. For many regions, maps have been made which show bands of average rainfall and temperature, usually correlated to elevation and other topographical features.

  Agriculturalists and other local people, dependent upon favorable temperature and rainfall for a successful harvest, are careful observers of the climate. They often have elaborate methods of predicting changes in the weather from one year to the next, based on observations of the atmosphere, the behavior of animals, the timing of temperature changes and the onset of rainfall. These phenomena are closely related to the agricultural calendar, which governs when to prepare the soil, sow seed, harvest and perform other tasks. Local people also have a keen sense of Microclimates, the small localized variations in climate which allow a particular vegetation or cultivated plant to prosper.

  Although climate is not something that can be seen or touched, everyone is aware of it. Yet if you cannot point to a climate zone and ask its name, how do you elicit the local categories? You will probably hear some climate terms mentioned in everyday conversation, especially when people are talking about agricultural production or the location of a settlement: ‘This corn grows in cold country’ or ‘His ranch is in the hot zone’. Because each term is likely to have a common word such as ‘country’, ‘place’ or ‘land’, you can ask for other similar expressions. For example, I learned that the village of Totontepec is located in mukojk an it, the ‘temperate zone’. After enquiring for other zones, I was told that ‘hot land’ was called an it and ‘cold country’ xox it.

  After obtaining a complete list of names, ask local people to draw a map showing the limits of each climate zone in the community. Local people characterize broad climatic zones by temperature ranges and rainfall. They can make a diagram of how these and other factors vary seasonally in each climate zone. With community weather records or climate and topographic maps in hand, you can estimate the temperature, precipitation and elevational limits of each area.

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  Tropical Rain Forest Ecosystems

  Biogeographical and Ecological Studies

  • H. Lieth, M.J.A. Werger(Authors)
  • 2012(Publication Date)
  • Elsevier Science

    (Publisher)

  Chapter 3 VERTICAL STRATIFICATION IN MICROCLIMATE T A T U O K I R A and KYOJI Y O D A INTRODUCTION Information from publications before 1950 on the microclimate in tropical rain forests was well compiled and reviewed by Richards (1952). Sum-marized accounts have also been given by Walter (1964, 1971), Longman and Jenik (1974), Leigh (1975), Whitmore (1975) and Bazzaz and Pickett (1980), among others. As far as general patterns of the microclimate are concerned, there is little to add to this literature. However, microclimatology has undergone a fundamental change in recent years with the development of both instruments and theories (see, for instance, Monteith, 1975, 1976). Only a few field studies made in the tropical rain forest have been based on the new approach of microclimato-logy, in which the observation of vertical gradients of meteorological elements in and above the leaf canopy plays an essential role. Examples are the studies by Odum et al. (1970) in a montane rain forest at El Verde, Puerto Rico; by Chunkao (1971) in a semi-evergreen seasonal forest at Sakaerat, Thailand; by Allen et al. (1972; see also Allen and Lemon, 1976) in an old secondary forest at Turrialba, Costa Rica; and by Aoki et al. (1975) in a lowland rain forest of Pasoh Forest Research Center, Peninsular Malaysia. In forest communities, particularly in tall tropi-cal forests, the height of trees is the greatest obstacle that must be overcome for ecological studies. This is particularly true of microclimatolo-gical studies. Walk-up towers built in several places in the tropical rain-forest zone, such as those at Sakaerat Experiment Station of northeastern Thai-land, Ulu Gombak near Kuala Lumpur and Pasoh Forest Research Center of Peninsular Malaysia, Barro Colorado Island of Panama, and the Forest Experiment Station at Beiern in Brazil have been extremely useful, but were not always used for microclimatological observations.

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