Severe Frost Research Articles

Freezing–thawing curves of earthen bricks with dielectric measurement: Insight into the influence of pore structure and initial moisture content

Under cold climate, poral water of building materials can be exposed to freezing–thawing (F–T) cycles that induce severe frost damage and jeopardize their durability. The F–T curve (variation in ice or unfrozen liquid content with negative temperatures) is a key property to examine and predict the behavior of porous materials under freezing temperatures. However, there is a lack of adapted procedures to evaluate the F–T curves of unsaturated earthen bricks. To fill this gap, this study proposes an experimental protocol, based on time domain reflectometry (TDR), to quantify the remaining liquid water in unsaturated earthen building materials at different temperatures from ＋10 °C to −20 °C. The validity of the device developed to determine F–T curves was verified with low temperature calorimetry (LTC). The dielectric measurement with TDR provides consistent quantification of remaining liquid water content with freezing temperatures. In this study, the influence of initial moisture conditions was investigated through both normal and pathological humid situations of earthen buildings. The normal service situation in winter season was studied with samples conditioned at relative humidity (RH) of RH75% and RH95% which lead to initial liquid saturation SL0 lower than 35% in the tested materials. The moisture pathological case was investigated with initial liquid saturation degrees of 75%, 85% and 95%. The necessary condition of water freezing in earthen materials, in function of their initial saturation ratio or conditioning relative humidity, was examined through a microstructural analysis. This approach also brought understanding about the dependency of the remaining unfrozen water with the freezing temperature.

Relationship of Indicators of Electrophoretic Analysis of Gliadin Protein in Different Triticum aestivum Varieties With Grain Quality

Data on the electrophoretic analysis of gliadin reserve proteins of 17 Triticum aestivum land varieties developed at the Research Institute of Agriculture are presented. As a result of the study, a wide polymorphism between varieties was established. The species differ from each other in all electrophoretic components. No matter how great this difference was, during the selection process, special attention was paid to the chromosomes Gld 1A and Gld 1B and Gld 1D. The high occurrence of the block of gliadin components GLd 1D is associated with the absence of severe frosts and the fact that most of the territories belong to the arid zone. The coincidence of the blocks of components GLd 1A5, GLd 1A4 and GLd 1B1 is due to the fact that their joint presence in the genotype has a positive effect on the quality of bread.

Validating local meteorological forecast knowledge in the Bolivian Altiplano: moving toward the co-production of agricultural forecasts

ABSTRACT This study validates local forecast indicators used by indigenous Aymara in Bolivia’s Northern and Central Altiplano. In Bolivia, the use of traditional forecasting methods is declining even though climate services cannot provide useful forecasts because of a low density of stations and lack outreach services. Validating local knowledge can reduce the erosion of local knowledge by resolving debates over their utility within communities and by gaining support of public agencies charged with promoting indigenous knowledge. The research had three phases, first key informants identified forecast indicators, then 95 farmers were asked to evaluate their reliability. In the North, four indicators were rated as highly reliable and in the Central region, three. Finally, a seasonal forecast indicator and two indicators of the onset of rains were evaluating using historical meteorological data. The seasonal indicator was the minimum temperature on the Fiesta de San Juan, and the rainy season onset was the flowering pattern of two plant species. The minimum temperature explained 55.5% of the variance in growing season precipitation. Flowering patterns are affected by severe frosts, and there was a correlation between frosts and later rains. Results show local knowledge’s potential for improving agrometeorological forecasts and for managing weather-related risks.

Frost Protection Case Study in Orchards

Abstract In two important fruit-growing areas of Hungary (Siófok, Pallag) we analyzed some frost protection methods used in practice, such as paraffin candles, frostbuster and frost protection irrigation. The frost protection experiment was set up by spraying the fruit trees with water at different intervals for half a minute. The canopy of each tree contained 4 thermometers, the average value of which was used to characterize the efficiency of frost protection irrigation. The effectiveness of frost protection in the canopy of the fruit tree can be characterized by the temperature measurable during the protection. The combined presence of sub-freezing water and ice, the freed heat of freezing, keeps the temperature near the protected flowers above 0 ° C, while the ambient air is up to -8 ° C. Frostbuster is a new frost protection technology developed primarily for frost protection in orchards. The device works by butane combustion and produces high (80-90 ° C) temperatures with strong air blowing. The device is towed by a tractor, so it is suitable for protecting up to 5-7 hectares. In the event of severe frosts, the tractor speed must be increased and it is advisable to reduce the size of the protected area. Paraffin candles are placed in a row between the trees. Between every tree or every second tree. As a result, up to a thousand paraffin candles can be placed in each hectare of the protected plantation. Applying them means a lot of human labor and high cost. Our study confirmed that Fostbusteres and paraffin candles only protect against frost up to -4 ° C, while antifreeze irrigation provided effective protection against frosts of up to -7 degrees.

Infiltration capacity in urban areas undergoing frequent snow and freeze–thaw cycles: Implications on sustainable urban drainage systems

Sustainable Urban Drainage Systems (SuDS) promote environmental protection and climate resilience. SuDS implementation in cold climates faces concerns of impaired hydrological function due to infiltration-reducing frost. The goal of this research was to assess the seasonal variations in infiltration and how different surface covers prevalent in and near coastal cities respond to frequent rain-on-snow and freeze–thaw cycles. A total of 28 constant head infiltration measurements were conducted over a period of 28 months in Urridaholt in Gardabaer, Iceland (64° 4′18.46″ N, 21° 54′37.11″ W) in a grass swale, lupine, and barren terrains. All test locations exhibited infiltration-inhibiting frost in winter, whose severity increased with frequent snow and freeze–thaw cycles. The grass swale resisted structural deformations resulting from frost, which was attributed to the high near-surface porosity within the intertwined root layer and the high drainage capacity of the underlying soil. The sparsely vegetated lupine and the barren area experienced severe frost heaving and cracking, and soil structural collapse which led to bypass flow upon thawing. The non-vegetated site had 30 to 50 times lower infiltration during winter (19 mm h−1) compared to the grass swale and lupine field (630- and 890-mm h−1, respectively), and twenty times lower during summer and fall (45 mm h−1 vs. ∼ 1000 mm h−1). The study concludes that frequent warming and cooling renders soils particularly vulnerable to frost. Vegetation plays an instrumental role in maintaining the hydrological functions of SuDS in winter. Therefore, the greening of urban centers is an important step towards climate resiliency. Plant selection and SuDS design criteria need to account for cold climate hydrological performance. In that regard, plants that limit sunlight and fully shed their vegetation in winter, such as the invasive lupine, can potentially contribute to frost formation and increase runoff generation.

The Geoecological Evaluation of the Heritage Interest of Polygonal Soils Inherited in Alpine Mountains. The Example of the Col du Noyer (Massif du Dévoluy, Hautes Alpes, France)

At an altitude of 1664 m, the Col du Noyer in the French Dévoluy Mountains, which is accessible in summer by road, is one of the most popular Alpine passes. It was located in an unglaciated area during the last Quaternary ice age and suffered the effects of the severe frost. Polygonal grounds formations have recently been discovered. Our study presents the results of the identification and characterisation of these formations as well as the floristic assemblages that currently occupy them. The analyses, carried out by a multidisciplinary team, consist of photo-interpretation, geomorphological, sedimentological and pedoanthracological studies. They confirm the presence of these inherited polygonal grounds. Floristic surveys reveal that these inherited periglacial formations constitute original habitats, favouring a strong local heterogeneity. The whole constitutes a natural complex requiring protection. Enhancing the heritage value of this site would constitute a means of protecting this complex, which is a rare geomorphological landscape in the Alps: educational both in terms of its understanding and its paleoenvironmental interpretation.

ОЦЕНКА АГРОМЕТЕОРОЛОГИЧЕСКИХ УСЛОВИЙ ПЕРЕЗИМОВКИ ОЗИМЫХ ЗЕРНОВЫХ КУЛЬТУР В АНОМАЛЬНО ТЕПЛЫХ ПОГОДНЫХ УСЛОВИЯХ 2019-2020 СЕЛЬСКОХОЗЯЙСТВЕННОГО ГОДА

The article analyzes the period of abnormally hot weather in the autumn and winter periods of 2019-2020 agricultural year, which was unprecedented and allowed the plants to overwinter successfully and even to go through a certain stage in their development and form a fairly high yield. It is a great anomaly with a typical return period of about 40 years. According to observations at Timiryazevsky agrometeorological post for 1990-2019, the average annual temperature increased by 1.04 ° С, atmospheric precipitation increased by 111.0 mm. The greatest increase of air temperature and atmospheric precipitation occurred in winter months. Analysis of wintering conditions for 2015-2020 agricultural years showed that positive temperature anomalies for the studied cold period of 2019-2020 reached up to 31.0 ° C. The amount of precipitation exceeded the average years long norms in November 2015 by 100 mm. Therefore, if earlier, the harvest of winter crops decreased due to freezing, as a result of snowlessness and severe frosts, then in recent years, soaking and asphyxiation played a certain role due to powerful snow cover. Such methods, as comparison, analysis and generalization of data, were used to process the analysis of the original data. To study the long-term changes of the periodic transformation function of the average annual temperature dynamics and the annual sum of atmospheric precipitation, the Fourier series was used and the parameters of the best sinusoidal approximation, the trend and the method of correlation, discriminant analysis were determined. The practical significance of the work was determined by the results of the research on the conditions for overwintering of winter crops and adaptation of agriculture to the changing conditions of the regional climate.

ANALYSIS OF THE STATION OF TOPIARY FIGURES ON THE TERITORI OF THE VINNYTSIA NATIONAL AGRARIAN UNIVERSITY

The article examines the relevance of topiary art in modern landscape design. The art of topiary requires a well-thought-out compositional integrity. Before choosing plants, you should decide on the theme of the garden and the harmonious arrangement of topiary figures in it. Such compositions become an adornment of any backyard territory, giving it an aristocratic exclusivity and originality. A detailed taxonomic analysis of the assortment of plants, which were used to form topiary on the territory of Vinnytsia National Agrarian University and the botanical garden "Podillya", was carried out. The state of the existing topiary figures was assessed. The features of the formation of topiary figures by the classical and wireframe formation technique have been investigated. Of the plants of the classical formation technique, a spiral figure has an excellent appearance. The hedge, cone and column shape have a good appearance. Plants formed in the form of a circle have the lowest indicators of external perception. The frame technique for creating plant compositions prevails at the VNAU exposition area. Project proposals have been developed to improve the aesthetics and general appearance of topiary figures on the territory of the Vinnytsia National Agrarian University. For the plant to have an attractive appearance, appropriate care is needed. Pruning of plants (sanitary) should be carried out only during the dormant period. The best period will be the end of winter, when the threat of severe frosts has passed. In the spring, no later than the first half of April, the first corrective pruning of figures and hedges should be carried out. In the summer, several additional haircuts are made, the frequency of which depends on the intensity of growth. It is optimal to carry out an additional haircut 3 months after the first one. In summer, you do not need to cut in extreme heat. Haircuts are finished before the onset of the first frost. If you carry out the formation later, then the created topiary will simply freeze over. In the cold season, some figures, especially those created from conifers, can fall apart under the weight of snow, so it is advisable to tie them up.

GRUBOŚĆ POKRYWY LODOWEJ WYBRANYCH JEZIOR O GENEZIE EOLICZNEJ, KRASOWEJ I RZECZNEJ W WOJEWÓDZTWIE ŚWIĘTOKRZYSKIM

The research covered three genetic groups of lakes (karst, aeolian, and riverine) which occur in Świętokrzyskie Voivodeship. Depending on the specific group, the lakes have different morphometric parameters of the lake basin and the water catchment area as well as physical and chemical properties of the water. In winter 2021, after a wave of severe frost, the thickness of the ice was measured on a selected number of lakes. The results of the tests indicate a diverse thickness of the ice caps. Karst lakes had the thickest ice caps. Riverine and aeolian lakes, on the other hand, featured similar thickness of the ice. However, it was noticed that in the case of riverine lakes, the ice cap on shores with prevailing reed was thinner than in the central parts of the lake.

Crop Cycle Length Determines Optimal Transplanting Date for Seedlings from Hybrid True Potato Seeds

AbstractThe technology of hybrid breeding in diploid potatoes creates opportunities to design novel and improved cultivation systems based on hybrid true potato seeds. A promising cultivation pathway to produce seed or ware tubers is by transplanting greenhouse-raised seedlings into the field. This study explored the effects of transplanting date and seedling age on tuber yield, using greenhouse-raised seedlings. Field trials with experimental hybrid genotypes were conducted in three consecutive years. In 2017 and 2018, 4- and 6-week-old seedlings were transplanted at four dates: March, April, May and June. In 2019, transplanting dates included April, May and June and seedling age was 5 weeks. In 2018, the March planting experienced severe frost during the initial field period resulting in crop failure. In 2017 and 2019, plants could withstand shorter and less severe frost events. Seedling age did not significantly affect tuber parameters. Transplanting in June resulted in lower marketable yield (> 28 mm) compared with earlier transplanting dates when crops were harvested in September. At full crop senescence, no differences in marketable yield were observed. The optimal transplanting window, taking into account weather-related risks, is approximately between early April and end May. For some genotypes, crop cycle length was observed to be a more important yield-determining factor than transplanting date.

30-year cone production dynamics in Siberian stone pine (Pinus sibirica) in the southern boreal zone: a causal interpretation

Background and aims – Siberian stone pine is a keystone species for Siberia, and numerous studies have analyzed Siberian stone pine seeding dynamics in connection with the dynamics of weather conditions. However, all studies were based on observations before 1990. The aim of the study was to expand our knowledge about the balance of weather and climatic factors in the regulation of cone production to enable conclusions about the current reproductive function in Siberian stone pine.Material and methods – We monitored Siberian stone pine cone production in the southeastern region of the Western Siberian Plain, in association with climatic factors, over a period of 30 years. To analyze the relationship with weather conditions, we used the trait mature cone number per tree and weather data obtained from the weather station in Tomsk.Key results – During this period, cone production decreased by about one-third, mainly caused by the complete absence of high yields. The main factor negatively affecting cone production was late spring frost: severe frost occurring with a large accumulated sum of effective temperatures resulted in full cone loss, and light frost substantially reduced cone number. A less important but significant climatic factor was September temperature: as the temperature increased, the cone number decreased in the following year. Over the last 30 years, the sum of the effective temperatures at which the last spring frost occurs, as well as the average September temperature, increased considerably, resulting in reduced cone production.Conclusion – If the current climatic trend is maintained, and especially if it is strengthened, Siberian stone pine cone production in the southern boreal forest zone on the Western Siberian Plane is unlikely to provide for the effective renewal of the species.

A new off-wall insulation liner for high-speed railway tunnels in cold regions

This paper has designed a novel off-wall insulation liner, aiming to prevent severe frost damages for the high-speed railway tunnel in cold regions. In terms of composition, the double-layer steel corrugated plates of the liner not only prevent the block falling and water intrusion of cold-region tunnels but prolong the durability and effectiveness of thermal insulation materials. Besides, the quick-construction technology for the off-wall insulation liner was derived in the present study, and it exhibits excellent construction efficiency, great economic and social benefits in the high-speed railway tunnel. Concerning the insulation capacity, the double insulation layers (polyurethane foam and air) perform the dramatical coldness-blocking effect, the freezing line moves forward from 0.48m-deep surrounding rock to the lining surface. The four-year field test has proved the effectiveness and insulation capacity of the off-wall tunnel, the severe frost damages in the Wufengshan tunnel were successfully eliminated. Compared with existing coldproof measures, the off-wall insulation liner in this paper exhibits excellent insulation capacity, high construction efficiency, and excellent economic benefits, it could be applied in the high-speed railway tunnels with high-altitude or extremely low temperatures.

A Review of Methods and Techniques for Detecting Frost on Plant Surfaces

Severe frost usually has adverse impacts on agricultural production, resulting in crop freeze injury, poor crop yield, and crop quality reduction. Timely and accurate detection of frost plays an important role in cold damage warnings, prevention, and control. Current frost detection methods mostly use physical properties such as light, electricity, and heat, or the judge and quantify using environmental factors such as temperature and wind speed. However, it is difficult to detect and accurately identify the frosting phenomenon in real time during field trials because of the complex environment, different plant types, and interference by many factors during observation. To provide an overview of the analytical tools for scientists, researchers, and product developers, a review and comparative analysis of the available literature on frost mechanisms, correlations, and characteristics are presented in this study. First, the mechanisms of the frost formation process, frost level, and the significance of detection, are introduced. Then, the methods and techniques used to measure frost on plant surfaces are synthetically classified and further compared. Moreover, the key points and difficulties are summarized and discussed. Finally, some constructive methods of frost detection are proposed to improve the frost detection process.

Anti-frost heave design method for a parabolic canal based on the hydraulic optimal solution set in seasonally frozen regions

Parabolic canals are commonly used in seasonally frozen regions because of their excellent hydraulic characteristics and frost heave resistance. However, severe frost damage can still occur, mainly because the design of canals is based on experience, and the analytical mechnical models and design methods are limited. First, the frost heave characteristics of parabolic canals were analysed, and the canal lining was simplified as an arched thin shell structure under the normal frost heave force, tangential freezing force, and gravity. Second, an analytical mechanical model of frost damage to the lining was established, and the equations for the axial force, bending moment, tensile stress were derived; the accuracy of the model was verified by field measurements and numerical simulations of a canal case. Third, the effects of groundwater depth and canal size were analysed, and the frost damage mechanism was investigated. Fourth, the anti-frost heave design method of a canal based on the hydraulic optimal solution set was proposed, and the method was encapsulated into digital design software with Python language. This mechanical model can explain the frost damage of the canal, and the nonuniform frost heave of foundation soil caused by different groundwater depths in different parts of the canal is the cause of lining damage. The bi-objective optimization design method can consider the hydraulic performance and anti-frost heave performance of the canal, and the digital design software can assist engineers with developing a quick and accurate design approach. The research results can provide a theoretical basis and technical means for cold-region canal design.

Severe frost but not shade could limit the future growing season of Erythronium americanum

Changes in climate are leading to modifications in the timing of seasonal events such as migrations and flowering. Erythronium americanum Ker Gawl. (trout lily) can break bud early in response to warming, but changes to its growing season may be limited by early shade from canopy trees and frost. I experimentally assessed the impact of shade and frost on senescence in E. americanum and descriptively monitored the response of E. americanum to vernal air and soil temperatures in a garden setting. Early shade did not affect the timing of senescence. Experimental exposure to frost resulted in increased leaf damage, earlier senescence, and greater corm death than in control plants. Despite 10 days in which the air temperature dropped below freezing, there was no evidence of leaf damage in the field. These results suggest that early shade from canopy trees will not hasten the end of the future growing season for E. americanum, but that late frost could bring about early senescence if that frost is sufficiently hard.

Evaluation of Frost Damage and Pod Set in Faba Bean (Vicia faba L.) under Field Conditions

Frost is one factor that causes extensive yield losses globally. A study was conducted to evaluate frost damage under field conditions and assess the genetic variation of flowers converting into pods. Diverse faba bean genotypes were evaluated under four growing seasons in a randomized complete block design: three at the University of Sydney, Narrabri, Australia (2014–2016) with three sowing dates, and one at the Agricultural Research Station, Dirab, Riyadh, Saudi Arabia (2016/2017) in one sowing. Visual methods were used to estimate frost damage and record the development of pods. Radiation frost in 2014 (Narrabri) damaged lower pods, while advection frost in 2016/2017 (Dirab) damaged upper pods. The radiation frost formed immediately above the ground; therefore, flowers and pods of taller plants minimized the damage because of their long distance from the ground. The earliest (mid-April) and middle sowing (7 May) suffered more by frost, while a delay in sowing (last week in May) led to frost escape or minor damage. The genotypes IX474/4-3 and 11NF010a-2 showed low sensitivity to frost at the vegetative and reproductive stages. Flowers developed at the beginning of flowering had a faster and higher pod formation rate (41–43%) than those formed later and contributed more to yields. Therefore, a severe frost at the beginning of flowering can cause a significant yield loss as these flowers are the most productive. The frost-tolerant genotypes, and faster and higher pod forming rates, identified in this study can be exploited to breed better varieties in the future.

An implicit Heat-Pulse-Probe method for measuring the soil ice content

• Ice content measurement in soil is essential and challenging, and the thermal response of frozen soil mainly depends on the pore ice content. • The pore ice content can be measured by its thermal response. • An implicit heat-pulse method is proposed to measure soil ice content. • T rela characterizes soil thermal response upon heating. • Ice content θ i affects soil thermal properties and thermal response T rela . • A standard calibration is proposed to determine the relation between T rela and θ i . • The average errors of θ i from the new method are around 3%. Soil ice content increases with time during the freezing process, thus frequently causing severe frost heave of subgrade or foundation in the cold region. It is a lasting challenge to implement real-time monitoring of soil ice content. In this study, a new heat-pulse method with an average accuracy of around 3% was proposed to measure soil ice content. This method was implemented by the following steps: (1) A heat pulse method with a double-probe sensor, i.e., one heating probe and one measurement probe was used; (2) In the calibration, the relation area after a heat-pulse action was measured on four samples with different initial water contents and at eight negative environmental temperatures. (3) On the calibrated data, an approximate function was fitted to characterize the monotonic relation between the relation area and soil ice content; (4) In application, the relation area value and environmental temperature were measured for each frozen sample, and the measurements were substituted into the approximate function to calculate the soil ice content. The effectiveness of the new method was verified by the test on three types of soil, including a silty clay, a sand loam, and a sand.

ОЦЕНКА ОБРАЩАЕМОСТИ ПАЦИЕНТОВ С БОЛЕЗНЯМИ СЕРДЕЧНО-СОСУДИСТОЙ СИСТЕМЫ ЗА МЕДИЦИНСКОЙ ПОМОЩЬЮ В НЕБЛАГОПРИЯТНЫЕ ПО МЕТЕОФАКТОРАМ ДНИ

Relevance. The impact of weather factors on the occurrence of exacerbations of diseases in weather-dependent people is currently one of the actively studied problems of medicine. A number of authors draw attention to the need to correct the functional status of weather-dependent patients with cardiovascular diseases in unfavorable weather conditions. Aim: to assess the possible relationship between the manifestations of exacerbations of cardiovascular pathology and adverse weather factors. Material and methods. The materials of the regional center for Hydrometeorology and environmental monitoring were used, and a database was formed that includes information on the average daily, maximum and minimum atmospheric air temperatures, and atmospheric pressure for each day of 2018. Results. Meteorological risk factors for exacerbation of cardiovascular diseases in the Central European part of Russia include uncharacteristic heat (above +30 0C) or severe frost (below -20 0C), sudden changes in air temperature (by 8 0C or more, both in the direction of its increase and decrease), atmospheric pressure drops of more than 6 mm Hg during the day. It is established that the range of changes in meteorological indicators during the annual cycle is quite wide. Conclusions. Evaluation of the relationship between the treatment of patients with leading forms of cardiovascular diseases for medical care and meteorological indicators (average daily, maximum and minimum atmospheric air temperatures, atmospheric pressure) showed that with the advance of the case of the disease by 1 day (hypertensive disease without heart failure, brain vascular lesions, cerebrovascular disease, hypertensive disease with heart failure, angina pectoris), statistically significant links of weak and moderate strength were revealed.

Multivariate Analysis of Seed Chemical Diversity among Jatropha curcas in Botswana

Jatropha (Jatropha curcas L.) has been identified as a potential bioenergy feedstock in arid regions, but knowledge of the diversity of its chemical characteristics is limited. In this study, 61 Jatropha accessions growing in Botswana, where both severe drought and winter frosts frequently occur, were analyzed for their seed chemical properties. Histogram analyses and meta-analysis comparisons with seeds from other countries/continents showed that the median/mean dry seed weight, toxic compound phorbol esters, and C18:0 fatty acid levels in the Botswanan accessions were lower than those from other countries/continents. A clustered heat map analysis indicated five clades for the Botswanan accessions, and their physicochemical traits were also categorized into five groups. Many positive and negative correlations were observed among the chemical traits, including negative correlations between the C18:3 (linolenic acid) content and yield-related traits (lipid content and dry seed weight). Principal component analysis highlighted the existence of accessions with highly deviated seed chemical compositions, such as those enriched in C18:0/C18:1 and C16:0/C16:1/C18:3 fatty acids. Overall, the present study suggests considerable diversity in the seed chemical compositions of Botswanan Jatropha accessions. Various accessions could be useful as feedstock for specific industrial products, as well as for breeding materials for the fortification of specific chemical ingredients.

A landscape assessment of frost damage in the northmost Neotropical dry forest

Extreme climatic and weather events are inducing widespread tree mortality in many forest ecosystems worldwide. A severe frost related to the historic cold wave that affected much of North America in early February 2011 triggered extensive tree mortality in the lowland tropical dry forest in northwestern Mexico. In this landscape, we assessed frost-induced vegetation damage using anomalies of the widely used NDVI spectral index calculated with a 12-year pre-disturbance reference period. In addition, NDVI anomalies were related to ground-based measures of frost-disturbance severity (density of frost-killed trees) and forest recovery (post-frost recruits and resprouting of surviving trees) obtained in 48 1-ha study plots distributed across the landscape. We found negative NDVI anomalies in 84% of our study area, indicating widespread frost-induced vegetation damage. The relationship between NDVI anomalies and density of frost-killed trees confirmed the level of frost damage across the lowland vegetation, suggesting that even small deviations from long-term mean NDVI values may hint to severe disturbance on forest structure and function. Higher frost-disturbance severity stimulated more new recruitment and less tree resprouting. Our results demonstrate the reliability of spectral indices for rapid assessment of climate-induced vegetation change, the high vulnerability of tropical dry forests to extreme frost and the predominant mechanism of vegetation recovery after severe frost disturbance.