Grass Surface Research Articles

Influence of ground surface characteristics on the mean radiant temperature in urban areas

The effect of variations in land cover on mean radiant temperature (T mrt ) is explored through a simple scheme developed within the radiation model SOLWEIG. Outgoing longwave radiation is parameterised using surface temperature observations on a grass and an asphalt surface, whereas outgoing shortwave radiation is modelled through variations in albedo for the different surfaces. The influence of ground surface materials on T mrt is small compared to the effects of shadowing. Nevertheless, altering ground surface materials could contribute to a reduction in T mrt to reduce the radiant load during heat-wave episodes in locations where shadowing is not an option. Evaluation of the new scheme suggests that despite its simplicity it can simulate the outgoing fluxes well, especially during sunny conditions. However, it underestimates at night and in shadowed locations. One grass surface used to develop the parameterisation, with very different characteristics compared to an evaluation grass site, caused T mrt to be underestimated. The implications of using high temporal resolution (e.g. 15 minutes) meteorological forcing data under partly cloudy conditions are demonstrated even for fairly proximal sites.

Biomechanical analysis of ankle during the stance phase of gait on various surfaces: a literature review

The purpose of this article is to review the literature that deals with the biomechanical analysis of the ankle during gait stance phase on slopes, on uneven and rock surfaces, on sand, and on grass surfaces, as well as to present the observed differences.MethodsThe literature was searched in the databases of PubMed and Google Scholar, for the years of 2005–2015. The keywords were: biomechanics, gait analysis, ankle joint, stance phase, uphill walking, downhill walking, sand surface, uneven surface, grass surface, and ballast.ResultsThe kinetic and kinematic gait behaviour is directly influenced by the surface on which it is being performed. The uphill or downhill surfaces, the surfaces of stone, sand, grass, and uneven surfaces have a direct impact on the biomechanics on joints of the lower limb, changing the energy cost, muscle activation, the resulting mechanical work, ground reaction forces and balance, and the parameters of the gait cycle. All these changes are raising many questions about the safety and comfort of these surfaces. In the structures of the foot, ankle and lower leg high compressive and rotational forces are transmitted resulting in injuries in these regions.ConclusionsEach surface has its own advantages and disadvantages, changing the biomechanics of the lower extremity and particularly the ankle. According to the purpose that one wants to achieve they can choose a suitable surface. To prevent injuries and falls, we must choose shoes that fit well, are comfortable with cushioning, and have a feeling neither too hard nor too soft, with laces and low collar.

English

Public safety is critical to the provision of sports fields and is dependent on maintaining natural grass surfaces and checking the safety of sports environments before play, to identify, remove and control hazards to reduce injury risk to participants. This paper presents and evaluates a Good Practice Sports Ground Inspection Form (GPSGIF), a new checklist developed to assist sports organizations, policy makers and field managers in the identification of injury hazards on natural grass fields. Use of the GPSGIF led to a consensus decision about the safety of grounds in >80% of assessments, and most items showed high levels of agreement. Comparisons of trained and untrained users showed that untrained assessors had higher levels of agreement, as they tended to rate grounds unsafe, suggesting they erred on the side of caution. The GPSGIF can be used by those responsible for sports field management to make consistent and evidence-informed decisions about field quality. Such assessments will provide athletes with the opportunity to compete in their chosen sport with minimized risk of injury. To enable a more thorough link between field conditions and injury, we would recommend that researchers’ use the GPSGIF in future subjective ground assessment work.

The Epidemiology of UK University Football Injuries within the 2011-2012 Season

Although football is one of the most popular sports worldwide, there have been very few studies on injuries suffered at university level. The aim of this study was to collate a wide range of epidemiological findings representative of the injuries suffered by those who play football at this level; while also comparing those injuries suffered between males and females. An electronic retrospective questionnaire was completed by 183 British University level footballers (males n=99, females n=84) who had sustained an injury during the 2011-12 season. The dominant lower limb (ankle: 29.5%, knee: 19.7%) was found as the most common site of injury occurrence with sprains (36. 6%) and muscle strains (23%) reported as the most common types of injury. University players are most often exposed to risk of injury in the autumnal period (20%), whilst playing a competitive match (58.5%) on a grass surface (66.1%) and the severity of injury is high (44.8%). Males reported more groin/thigh and muscle strain injuries compared to females. This study provides a landscape of information in relation to UK university football injuries. There is a need for an injury surveillance initiative to be implemented prospectively involving team doctors and a database of players’ medical records. This, in combination with the results found in this study, will help produce a better evidence base of the epidemiology of injuries at this level which will pave the way for producing preventative strategies that aim to improve the safety of university football participation.

Impact or push-off lameness presentation is not altered by the type of track surface where horses are trotted

This study aimed to evaluate the influence of the track surface on which horses are examined, regarding the phase of lameness presentation. Ten horses with lameness in at least one limb were evaluated with wireless inertial sensors on three track surfaces (concrete, loose sand and grass). Six crossover track sequences were established. The variables vector sum, maximum and minimum height of the head and pelvis, variation coefficient of the maximum and minimum height of the head and pelvis were analyzed using ANOVA, followed by Tukey test to compare means between track surface and sequence, at 5% significance level. The lameness phase (impact or pushoff) was analyzed considering the proportion of affected animals. There were no differences on vector sum, maximum and minimum height or variation coefficient of head and pelvis. Difference was observed on the number of strides registered on sand compared to grass and concrete (p <0.0001) for fore and hindlimbs. Impact lameness on forelimbs was presented by a larger number of animals on the concrete surface; pushoff lameness was more evident on the grass surface. In the hindlimbs, impact lameness was more evident on the grass surface, while pushoff lameness was in greater number of animals on concrete surfaces. The track sequence on which horses were trotted during evaluation does not seem to be a factor, but the number of lame horses and the phase of lameness manifestation can vary between track surfaces, as some horses showed impact lameness on soft ground and elevation lameness on hard ground.

The Influence of Different Training Conditions on the Kinematics of Long Jump-Specific Exercise in Young Female Jumpers

Abstract Introduction. This study examined the changes in the kinematic parameters of long jump-specific technical exercise performed in different training conditions. Material and methods. The study involved a group of young female athletes who volunteered to participate in the research. The key variables for long jump performance were measured using the Xsens MVN system. A three-way ANOVA (general linear model with repeated measures; factors: surface × hurdle × number of jumps) was used to determine if significant differences existed between the testing conditions. Results. The main finding of this study was that the tartan surface resulted in significantly (p < 0.05) greater velocities of the centre of mass of the body (CM) or parts of the athlete’s body than the grass surface. The second important finding was that the hurdles condition provided significantly (p < 0.05) greater velocity of the CM when landing and shorter contact time compared to the condition without hurdles. Conclusions. The findings of the study indicate that technical exercise should be performed on harder surfaces such as a tartan track rather than softer ones (e.g. grass) due to more beneficial movement characteristics and greater potential for the automaticity of movement during specific training tasks.

Equilibrium and Thermodynamic Studies of Reactive Orange Dye Biosorption by Garden Grass

The present study aims to evaluate the biosorption of reactive orange dye by using garden grass. Experiments were carried out in a batch reactor to obtain equilibrium and thermodynamic data. Experimental parameters affecting the biosorption process such as pH, shaking time, initial dye concentrations, and temperature were thoroughly examined. The optimum pH for removal was found to be 4. Fourier transform infrared spectroscopy analysis indicated that the electronegative groups on the surface of garden grass were the major groups responsible for the biosorption process. Four sorption isotherm models were employed to analyze the experimental data of which Temkin and Pyzhey model was found to be most suitable one. The maximum biosorption capacity was 12.2 mg/g at 30 °C. The maximum removal percent reached 90% at optimum conditions. Therefore, the pretreatment or modification of this biosorbent may enhance the biosorption capacity. Thermodynamic parameters (i.e., change in the free energy, the enthalpy, and the entropy) were also evaluated and their values revealed that the biosorption process was exothermic in nature and less favorable at high temperature.
 

The k−1 scaling of air temperature spectra in atmospheric surface layer flows

A number of atmospheric surface layer (ASL) experiments reported a k−1 scaling in air temperature spectra ETT(k) at low wavenumber k but other experiments did not. Occurrence of this scaling law in ETT(k) in an idealized ASL flow across a wide range of atmospheric stability regimes is investigated theoretically and experimentally using measurements collected above a lake and a grass surface. Experiments reveal a k−1 scaling persisted across different atmospheric stability parameter values (ζ) ranging from mildly unstable to mildly stable conditions (−0.1 < ζ < 0.2). As instability increases, the k−1 scaling vanishes. Based on simplified spectral and co‐spectral budgets and using a Heisenberg eddy viscosity as a closure to the spectral flux transfer term, conditions promoting a k−1 scaling in ETT(k) are identified. Existence of a k−1 scaling is shown to be primarily linked to an imbalance between the production and dissipation rates of half the temperature variance. When −0.1 < ζ < 0.2, such imbalance exhibits weak dependence on ζ and hence z, which is shown to be the main cause for a −1 scaling at low k. As the atmosphere becomes more unstable, the imbalance determined from experiments here are not significantly affected by ζ, thereby negating conditions promoting a −1 scaling in ETT(k). The role of the imbalance between the production and dissipation rates of half the temperature variance in controlling the existence of a −1 scaling suggests that the −1 scaling in ETT(k) does not necessarily concur with the −1 scaling in the spectra of longitudinal velocity Euu(k). This finding explains why some ASL experiments reported k−1 in Euu(k) but not in ETT(k).

Assessing the dye‐tracer correction factor for documenting the mean velocity of sheet flow over smooth and grassed surfaces

AbstractIn the investigation of overland flow hydraulics, mean flow velocity (V) is frequently estimated using the measured surface flow velocity (Vs) multiplied by a correction factor, α. In total, 291 tests were performed in a flume with three beds [smooth glass (GL), sandpaper (SD), and plastic grass (GR)] to investigate α under submerged and non‐submerged flows, and Vs was observed using dye‐tracer method whilst V was calculated by the measured water depth and flow rate. For GL with 5.2% slope and 100 < Re < 5000 [Reynolds number (Re)], α ranged from 0.35 to 0.79, with an average of 0.54. For SD with slopes ranging from 2.6% to 25.9% and 300 < Re < 1200, α varied from 0.18 to 0.48 with an average of 0.32. Raindrop impacts decreased α for GL at 5.2% slope, but the effect diminished for SD as the slope increased. The α‐values less than the theoretical value of 0.67 in laminar flows may be attributed to the greater spatial variability in overland flow compared with channel flow. For GR with non‐submerged flows and Re < 4200, α varied inversely with sediment concentration (SC) at 5.2% slope but was only slightly related to SC at steep slopes of 15.6% and 25.9%. The α‐values were approximately 0.8 for turbulent flows and even greater than 1.0 under high flow discharges. This finding may relate to sheet flow disturbance and retarded surface velocity due to the protruding scattered grass stems. For each surface, α varied positively with Re; α was inversely related to slope for SD but positively related to slope for GR. There was a positive relation between h and α for GL and SD but a negative relation for GR, which highlights the importance of flow inundation status to α. The inundation ratio (h/Δ) is a promising indicator for predicting α; thus, further investigations using different submerged and non‐submerged surfaces are required to predict α effectively based on (h/Δ). Copyright © 2015 John Wiley & Sons, Ltd.

Temporal Variations in the Surface Soil Heat Flux over Maize and Grass Surfaces in Northwest China

Surface soil heat flux (G(0)) is an indispensable component of the surface energy balance (SEB) and is important for estimating instantaneous surface evapotranspiration (ET). Many studies suggest that daily or longer timescales of G(0) can be ignored, whereas other studies suggest the opposite. In this study, a long-term G(0) was calculated using a heat conduction equation based on observed soil temperature and moisture profiles over 30-min intervals from January 2008 to December 2011. Maize and meadows covered the study area in the Heihe River Basin (HRB), northwestern China. The effects of various timescales of G(0) (half-hourly, daily, monthly, and yearly) on energy balance closure (EBC) and ET estimations were quantitatively analyzed. The results showed that the diurnal G(0) had the same magnitude as the sensible heat flux, and it increased the EBC by 12.9 and 8.2% in maize and grasslands, respectively. The maximum daily G(0) reached 20% of the net radiation, and the maximum monthly ET was overestimated by 15% when neglecting the monthly G(0) over the bare soil when the maize has not germinated. The yearly G(0) values were nearly zero in maize and grasslands and were excluded. Thus, the G(0) is important for EBC and ET estimation with shorter timescale than annual timescale. The G(0) should not be neglected except for annual timescale.

Impacts of Different Urban Surfaces on Summer Thermal Performance

This study measured temperatures and albedos of urban surfaces for different colors and materials during summer, and calculated the energy budget over different urban surfaces to find out the thermal performance affecting the heat built-up. The study selected six surface colors and 13 materials common in urban landscape. Their surface temperatures (Ts) and albedos were measured at a given time interval in the daytime from June to August. Average Ts over summer season for asphalt-colored brick was <TEX>$4.0^{\circ}C$</TEX> higher than that for light red-colored one and <TEX>$9.7^{\circ}C$</TEX> higher than that for white-colored one. The Ts for artificial surface materials of asphalt paving, brown brick wall, and green concrete wall was <TEX>$6.0^{\circ}C$</TEX> higher than that for natural and semi-natural ones of grass, grassy block, and planted concrete wall. There was the greatest difference of <TEX>$16.3^{\circ}C$</TEX> at midafternoon in the Ts between asphalt paving and planted concrete wall. Average albedo over summer season of surface materials ranged from 0.08 for asphalt paving to 0.67 for white concrete wall. This difference in the albedo was associated with a maximum of <TEX>$15.7^{\circ}C$</TEX> difference at midafternoon in the Ts. Increasing the albedo by 0.1 (from 0.22 to 0.32) reduced the Ts by about <TEX>$1.3^{\circ}C$</TEX>. Average storage heat at midday by natural and semi-natural surfaces of grass and grassy block was about 10% lower than that by artificial ones of asphalt, light-red brick, and concrete. Reflected radiation, which ultimately contributes to heating the urban atmosphere, was 3.7 times greater for light-red brick and concrete surfaces than for asphalt surface. Thus, surfaces with in-between tone and color are more effective than dark- or white-colored ones, and natural or semi-natural surfaces are much greater than artificial ones in improving the urban thermal environment. This study provides new information on correlation between Ts and air temperature, relationship between albedo and Ts, and the energy budget.

Accuracy Assessment of NOAA Gridded Daily Reference Evapotranspiration for the Texas High Plains

AbstractThe National Oceanic and Atmospheric Administration (NOAA) provides daily reference evapotranspiration (ETref) maps for the contiguous United States using climatic data from North American Land Data Assimilation System (NLDAS). This data provides large‐scale spatial representation of ETref, which is essential for regional scale water resources management. Data used in the development of NOAA daily ETref maps are derived from observations over surfaces that are different from short (grass — ETos) or tall (alfalfa — ETrs) reference crops, often in nonagricultural settings, which carries an unknown discrepancy between assumed and actual conditions. In this study, NOAA daily ETos and ETrs maps were evaluated for accuracy, using observed data from the Texas High Plains Evapotranspiration (TXHPET) network. Daily ETos, ETrs and the climatic data (air temperature, wind speed, and solar radiation) used for calculating ETref were extracted from the NOAA maps for TXHPET locations and compared against ground measurements on reference grass surfaces. NOAA ETref maps generally overestimated the TXHPET observations (1.4 and 2.2 mm/day ETos and ETrs, respectively), which may be attributed to errors in the NLDAS modeled air temperature and wind speed, to which reference ETref is most sensitive. Therefore, a bias correction to NLDAS modeled air temperature and wind speed data, or adjustment to the resulting NOAA ETref, may be needed to improve the accuracy of NOAA ETref maps.

Estimation of external dose by car-borne survey in Kerala, India.

A car-borne survey was carried out in Kerala, India to estimate external dose. Measurements were made with a 3-in × 3-in NaI(Tl) scintillation spectrometer from September 23 to 27, 2013. The routes were selected from 12 Panchayats in Karunagappally Taluk which were classified into high level, mid-level and low level high background radiation (HBR) areas. A heterogeneous distribution of air kerma rates was seen in the dose rate distribution map. The maximum air kerma rate, 2.1 μGy/h, was observed on a beach sand surface. 232Th activity concentration for the beach sand was higher than that for soil and grass surfaces, and the range of activity concentration was estimated to be 0.7–2.3 kBq/kg. The contribution of 232Th to air kerma rate was over 70% at the measurement points with values larger than 0.34 μGy/h. The maximum value of the annual effective dose in Karunagappally Taluk was observed around coastal areas, and it was estimated to be 13 mSv/y. More than 30% of all the annual effective doses obtained in this survey exceeded 1 mSv/y.

Hierarchical Nanofeatures Promote Microbial Adhesion in Tropical Grasses: Nanotechnology Behind Traditional Disinfection

Desmotachya bipinnata L. (Darbha) is a tropical grass used as an inevitable material in traditional practices and rituals of the Indian Hindus. Darbha, the sacred grass has been used to prevent spoilage of fermentable food during solar and lunar eclipses, which is being followed even today. However, the reason for choosing this grass among several other grass species has not been reported. In this work, while exploring the reason behind the choice of this grass for traditional practices, interesting hierarchical nanoscale morphology of Darbha grass revealed in scanning electron microscopy. To understand the role of Darbha in food preservation during eclipse, cow’s curd has been chosen a representative fermentable food item. Systematic investigation on Darbha grass grown in three different microhabitats has been performed, and their effect on the population and diversity of lactobacilli from cow’s curd has been studied. Interestingly, the grass with the most prominent nanoscale features is found to remove most of the lactobacilli from cow’s curd. Thus, Darbha reduces microbial accumulation in fermentable food items when the bactericidal ultraviolet and blue radiations are not available to the earth surface during eclipse. The disinfecting ability of Darbha is compared with five other tropical grasses chosen on the basis of presence/absence of micro/nanofeatures, antibacterial effect and hydrophobic surface. The other grasses used in this study are Chloris Barbata L., Apluda aristata L., Cynodon dactylon L., Bamboosa arundinacae L. and Cymbopogon citratus L. Based on comparative studies with these grasses, the mechanism of disinfecting ability of Darbha is attributed mainly to the hierarchical micro/nanofeatures present on the grass surface. The results of the present investigation could be used to design novel biomimetic antibacterial surfaces for applications including health care.

The mechanical interactions between an American football cleat and playing surfaces in-situ at loads and rates generated by elite athletes: a comparison of playing surfaces

This study quantified the mechanical interactions between an American football cleat and eight surfaces used by professional American football teams. Loading conditions were applied with a custom-built testing apparatus designed to represent play-relevant maneuvers of elite athletes. Two natural grass and six infill artificial surfaces were tested with the cleated portion of a shoe intended for use on either surface type. In translation tests with a 2. 8-kN vertical load, the grass surfaces limited the horizontal force on the cleats by tearing. This tearing was not observed with the artificial surfaces, which allowed less motion and generated greater horizontal force (3.2 kN vs. 4.5 kN, p < 0.05). Similarly, rotation tests generated less angular displacement and greater torque on the artificial surfaces (145 N m vs. 197 N m, p < 0.05). Translation/drop tests, in which the foot-form was launched into the surfaces with both horizontal and vertical velocity components generated less peak horizontal force on the natural surfaces than on the artificial surfaces (2.4 kN vs. 3.0 kN, p < 0.05). These results suggest a force-limiting mechanism inherent to natural grass surfaces. Future work should consider implications of these findings for performance and injury risk and should evaluate the findings' sensitivity to cleat pattern and playing conditions.

Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces.

Background:Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. Objective:To test whether different types of surfaces promote changes in the amplitude (ACOP) and velocity (VCOP) of the center of pressure (COP) displacement during the rider's contact with the saddle on the horse's back. Method:Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. Results:ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019). The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006). The VCOP did not differ between the surfaces. Conclusion:Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

A New Dew and Frost Detection Sensor Based on Computer Vision

AbstractMany weather features such as precipitation and snow depth can be recorded using automatic surface observation systems. However, automatically observing dew and frost presents several problems. Many studies have used various wetness sensors and passive microwave devices to detect dew. Unfortunately, several of these sensors are complex, and only a few are capable of detecting frost. This paper proposes a novel method for indirectly detecting dew and frost based on computer vision. The setup is simple, inexpensive, and only requires images of several glass substrates near the underlying surface. Images taken during dew or frost formation exhibit distinct changes in hierarchical visual features. These changes are detected by tracking the variations of several low-level statistical features that are extracted from the images in time. Additionally, an effective texture analysis method is proposed to describe the morphology of frost. Field experiments were conducted at several weather stations in Beijing, China. The validation of the method for measuring the onset and duration of dew/frost on short grass shows that 1) the proposed computer-vision-based algorithm achieves an accuracy of approximately 90% in discriminating among dewy, frosty, and dry nights based on the hourly manual observations of the grass surface and 2) the algorithm is also capable of measuring the duration of dew and frost on grass with about 70% accuracy.

The enhancement of biological ocular UV radiation on beaches compared to the radiation on grass

BackgroundThe influence of albedo on ocular UV exposure has seldom been reported. This paper aimed to explore the enhancement effect on measured ocular UV radiation due to a sand surface compared to measured ocular UV radiation due to a grass surface. MethodsWe measured ambient and ocular UV radiation over the beach and grass surface in Sanya City of China (18.4°N, 109.7°E). The experimental apparatus was composed of a manikin and a dual-detector spectrometer. Integration of both UVA and UVB radiation was used to denote UV radiation. Then biologically effective ocular UVB radiation (UVBE) and the ratios of UVBE of two surfaces were calculated. ResultMaximum of ocular UV radiation versus time over the two surfaces is bimodal. UVBE on the beach is significantly larger than UVBE on the sand, and UVBE peaked at different solar elevation angle (SEA) over the two surfaces (about 53° and 40° on the beach and grass, respectively, according to Bayesian regression). The maximum of ocular UVBE ratios is greater than two, which peaked SEA was about 50°. One hour’s cumulative radiation under sunny weather exceeds thresholds for photokeratitis, conjunctivitis and lens damage. ConclusionsHigher albedo significantly increased biological ocular UV radiation. Tourists on tropical beaches should take protective measures and avoid facing the sun directly, especially when SEA is around 50°.

Understanding pavement-surface energy balance and its implications on cool pavement development

The idea of using cool pavements to mitigate the urban heat island has gained momentum recently. Many studies have focused on the temperature of a cool pavement, whereas limited studies have reported on the pavement's sensible heat to the surrounding air. This paper demonstrates the energy partition at the ground surface, with focuses on the sensible heat releasing from the pavement surface. The energy partition of a typical dry pavement is simulated and compared to that at an irrigated grass surface. Pavements with different surface albedos and different thermal inertia are simulated to demonstrate influences of surface modification and heat-storage modification on the releasing sensible heat. Instantaneous solar absorption by the pavement is prone to be partitioned into heat conduction. Most of the absorption is discharged as sensible heat and long-wave emission, whereas the daily cumulative heat conduction is roughly 5% of the absorption. Both increasing the surface albedo and enhancing the evaporative flux are effective to suppress the sensible heat and to promote cool pavements. Raising the thermal inertia of the pavement decreases the sensible heat during the daytime but increases this factor at nighttime. Therefore, it should be cautious to design cool pavements by varying their thermal inertia.

CONFORTO TÉRMICO DOS USUÁRIOS EM VEGETAÇÃO E REVESTIMENTOS URBANOS NO CAMPUS DA UFMT EM CUIABÁ-MT

The thermal comfort of users, when experienced within acceptable standards, contributes to the use of green areas in urban environments, both for circulation and for leisure. The purpose of this paper is to evaluate the thermal comfort of users of the campus of Federal University of Mato Grosso/Cuiaba, at different types of soil covering and near arboreous vegetation. Measurements of micrometeorological variables were performed on campus. Initially four points that presented different types of floor covering, named soil, grass, concrete and asphalt were chosen on campus. Data were recorded for 43 continuous days in two seasons: hot -wet and hot-dry during the year of 2012. The data recorded during the day in the shade of mango tree (Mangiferaindica) found the lowest values of dry bulb temperatures (Tbs), compared to other places averages with different types of surfaces. The thermal perception “neutral or comfortable”, measured by Physiological Equivalent Temperature (PET), happened only at night from 19h to 07h. The grass surface presented comfortable thermal sensation, which may serve as indicator to increase spaces with this type of surface instead waterproof surfaces. As a result, it was observed in decision trees the preference, in the wet warm season, the variable “place” in both PET indices, highlighting the mango tree and grass surface in one group, and concrete and asphalt surfaces in another, while in the hot dry season, was indicated the wind speed as the main variable, and the variable “place” at the secondary level. Therefore, only at night it is possible to achieve the thermal comfort range. In the daytime, at shade of the mango tree, PET is much lower than at other measuring points, in both measurement periods, reaching a maximum of 35.4 °C at 15h in the second period. These findings might confirm the importance of providing shade in open spaces, and the choice, when possible, of grass surfaces (Paspalumnotatun) instead of soil, concrete or asphalt surfaces, and that concrete can be preferred over asphalt because have higher thermal exchanges in tropical climates. The percentage of comfortable and tolerable for the researched site was high, indicating a strong adaptation of users to the climate of Cuiaba/MT.