The influence of land-cover type on the relationship between NDVI–LST and LST-Tair

Air temperature (T_2m or T_air) measurements from 20 ground weather stations in Berlin were used to estimate the relationship between air temperature and the remotely sensed land surface temperature (LST) measured by Moderate Resolution Imaging Spectroradiometer over different land-cover types (LCT). Knowing this relationship enables a better understanding of the magnitude and pattern of Urban Heat Island (UHI), by considering the contribution of land cover in the formation of UHI. In order to understand the seasonal behaviour of this relationship, the influence of the normalized difference vegetation index (NDVI) as an indicator of degree of vegetation on LST over different LCT was investigated. In order to evaluate the influence of LCT, a regression analysis between LST and NDVI was made. The results demonstrate that the slope of regression depends on the LCT. It depicts a negative correlation between LST and NDVI over all LCTs. Our analysis indicates that the strength of correlations between LST and NDVI depends on the season, time of day, and land cover. This statistical analysis can also be used to assess the variation of the LST–T_2m relationship during day- and night-time over different land covers. The results show that LST_Day and LST_Night are correlated significantly (p = 0.0001) with T_2mDay (daytime air temperature) and T_2mNight (night-time air temperature). The correlation (r) between LST_Day and T_Day is higher in cold seasons than in warm seasons. Moreover, during cold seasons over every LCT, a higher correlation was observed during daytime than during night-time. In contrast, a reverse relationship was observed during warm seasons. It was found that in most cases, during daytime and in cold seasons, LST is lower than T_2m. In warm seasons, however, a reverse relationship was observed over all land-cover types. In every season, LST_Night was lower than or close to T_2mNight.     

Assessment of rainfall and NDVI anomalies in Spain (1989–1999) using distributed lag models

In this study a link was established between anomalies in climatic and Advanced Very High Resolution Radiometer (AVHRR)/Normalized Difference Vegetation Index (NDVI) data in Spain for the period from 1989 to 1999 on a monthly and annual basis using multivariate distributed lag (DL) models and generalized least‐square (GLS) parameter estimation. In most areas significant time‐delayed correlation between anomalies of monthly rainfall and NDVI data was confined to an interval of 1 month. Locally higher lag orders of up to 3 months were found. By contrast, relationships between surface temperature and the NDVI were insignificant in the multivariate context at most locations. The multiple correlation coefficients of the DL models achieved 0.6 in the maximum. Regions characterized by the most significant NDVI–rainfall correlations include the southern forelands of the Pyrenees in Catal?na, rainfed agricultural areas in Extremadura, Andalusia, and the western parts of Castilla y Leon. Average ratios of rainfall to potential evapotranspiration (PET) in the sensitive areas ranged between 0.5 and 2, with annual rainfall amounts less than 700 mm. For each land‐cover class a linear discriminant analysis (LDA) was carried out to assess the environmental factors that might explain the differences in the NDVI–rainfall relationships. The highest discriminant coefficients and factor loadings were recorded for those factors that recurrently trigger water deficit in the sensitive regions, such as low total annual rainfall, large seasonal rainfall variability, high average PET and surface temperature. On the annual basis the lagged correlation of the NDVI and rainfall data was confined to natural vegetation (grassland and scrubland) areas in western Spain. This region suffered from a severe drought in the early 1990s, after which biomass production lagged several years behind improved rainfall conditions. The approach presented is useful for assessing the influence of climatic variables on the pattern of temporal anomalies in the NDVI or related vegetation parameters.     

Spatial patterns of the NDVI–rainfall relationship at the seasonal and interannual time scales in an African savanna

Climate change is predicted to affect both the mean annual rainfall and its seasonal distribution over the African continent. Understanding their respective influences on primary production, an ecosystem's key feature, is therefore a major challenge for rangeland ecologists. We have investigated the change in intra‐ and interannual Normalized Difference Vegetation Index (NDVI) in relation to rainfall in Hwange National Park, Zimbabwe. Two distinct NDVI time series were built using NOAA/AVHRR data for the period 1982–2002. Long‐term monthly means described the change in seasonal NDVI, whereas annually integrated NDVI related to year‐to‐year fluctuations. The rainfall–NDVI relationship was stronger along the seasonal course [with a lag of 1 month, Kendall's tau (τ) = 0.879] than when studied interannually (τ = 0.476). Principal component analysis (PCA) demonstrated that spatial patterns of the NDVI fluctuations differed when studied interannually or during the seasonal course. Field features such as topography or vegetation composition influenced seasonal NDVI values whereas only rainfall distribution played a role at the interannual time scale. Our results show that rainfall controls on primary production and their mitigation differ between time scales, and these findings bring insights on the future response of savannas to climate change.     

The role of the kinetic parameter in the stability of two-relaxation-time advection–diffusion lattice Boltzmann schemes

In general, explicit numerical schemes are only conditionally stable. A particularity of lattice Boltzmann multiple-relaxation-time (MRT) schemes is the presence of free (“kinetic”) relaxation parameters. They do not appear in the transport coefficients of the modelled second-order (macroscopic) equations but they have an impact on the effective accuracy and stability of the algorithm. The simplest uniform choice (the well known BGK/SRT model) is often inadequate, and therefore a compromise in the complexity of the model is sought. For this purpose, the von Neumann stability analysis is performed for the d1Q3 two-relaxation-time (TRT) advection–diffusion model. The extended optimal (EOTRT) model, which relates the two collision times such that the most stable scheme is set by a suitable choice of the equilibrium parameters, equal for any Peclet number, is then developed. This extends the very recently derived optimal subclass (OTRT) to larger combinations of “physical” and “kinetic” collision rates. Next, we provide the necessary and/or sufficient stability limits on the EOTRT subclass for a wide range of velocity sets, with and without numerical diffusion, and delineate the interesting choices of free equilibrium weights for the d2Q9 and d3Q15 models. The BGK/SRT model is without advanced advection properties; we prove (for minimal stencil schemes d1Q3, d2Q5 and d3Q7) that the non-negativity of the equilibrium distribution is necessary for its stability in the advection-dominated limit. Beyond the EOTRT and BGK/SRT subclasses of the TRT model, blind choices of the “ghost” collision number may result in quite unstable schemes, even for positive equilibrium. However, we find that the d1Q3 stability curves govern the advection properties of the multi-dimensional models and a fuller picture of the TRT stability properties begins to emerge.     

The relationship between the leaf area index (LAI) of rice and the C‐band SAR vertical/horizontal (VV/HH) polarization ratio

We investigated the relationship between the leaf area index (LAI) of rice and the ENVISAT Advanced Synthetic Aperture Radar (ASAR) vertical/horizontal (VV/HH) polarization ratio. Four alternating polarization ASAR images of swaths IS4 and IS5 over rice fields were used in the study. The VV/HH polarization ratio correlates well with the field‐measured LAI and an empirical relationship was established to estimate the LAI of rice using the VV/HH polarization ratio. A theoretical radiative transfer model was adopted to analyse the relationship. The error of the estimated LAI was 0.17 for the test site and a better correlation was found when LAI was less than 3.5. The results suggest that ASAR alternating polarization data can be used to estimate the LAI of rice for wide‐area monitoring of rice growth.     

The Electronic Record in the school–family relationship: perceptions of teachers and guardians

Universal Access in the Information Society - This paper presents the first stage of an investigative work, the purpose of which is to introduce a new form of communication between schools and...     

NAO influence on NDVI trends in the Iberian peninsula (1982–2000)

This Letter describes analysis of the trends of NDVI in the Iberian peninsula from 1982 to 2000. The results were compared with the influence of the North Atlantic Oscillation (NAO) index. Significant spatial differences emerge in vegetation trend analysis, identifying a positive trend in the northern part and stability or negative trends in the south. Such a spatial pattern is significantly related to NAO influence on vegetation, which is linked to precipitation distribution in the Iberian peninsula and greatly influenced by this atmospheric pattern. The relationships between vegetation trends and NAO are discussed in detail.     

Yield estimation of winter wheat in the North China Plain using the remote-sensing–photosynthesis–yield estimation for crops (RS–P–YEC) model

The accurate prediction of crop yield is of great help for grain policy making. By assuming a horizontally homogeneous, vertically laminar structure and introducing a multilayer-two-big-leaf model, we develop a radiative-transfer equation for winter-wheat canopy and a model, named the remote-sensing–photosynthesis–yield estimation for crops (RS–P–YEC) model, for winter-wheat yield estimation. The yield is calculated by multiplying the net primary productivity (NPP) by the harvest index (HI). In this study, the yield of winter wheat in the North China Plain in 2006 is estimated using the RS–P–YEC model. The simulated yield is consistent with observations from 17 agro-meteorological stations, and the mean relative error is 4.6%. The results demonstrate that the RS–P–YEC model is a useful tool for winter-wheat yield estimation in the North China Plain with widely available remotely sensed imageries.     

The Changing Capabilities of Cohorts of the Elderly in Russia during 1990–2020: Measurement using a Quantitative Index

Russia has had a high elderly share of its population like the OECD countries, but has had a more turbulent history over the past 100 years, which has caused fluctuations in the capabilities of those turning 60 (measured by education and training, income, enabling environment, medical care, and health status). This article analyses the life experiences and capabilities of five Russian birth cohorts turning 60 over the period 1990–2020. It presents relevant concepts, reviews past research, and evaluates the importance of health factors (health environment, health-related behaviours, medical care, health status) in determining the activities and contributions of older people in Russia. A Human Capabilities of the Elderly in Russia Index (HCERI) with 22 indicators is developed. Russian data are used in the calculation of the HCERI for the cohorts turning 60 in 1990, 1995, 2000, 2010 and 2020. The article then presents evaluations of the experiences and changes in capabilities for each of the five selected cohorts of the elderly in four periods of life: Childhood (1–15 years), Young Adult (16–49), Mature Adult (50–59), and Early Elderly (60–69). The implications of changes in the characteristics of the elderly for Russian government policies are discussed.     

Estimating soil moisture using Temperature–Vegetation Dryness Index (TVDI) in the Huang-huai-hai (HHH) plain

Soil moisture is an important indicator to describe soil conditions, and can also provide information on crop water stress and yield estimation. The combination of vegetation index (VI) and land surface temperature (LST) can provide useful information on estimation soil moisture status at regional scale. In this paper, the Huang-huai-hai (HHH) plain, an important food production area in China was selected as the study area. The potential of Temperature–Vegetation Dryness Index (TVDI) from Moderate Resolution Imaging Spectroradiometer (MODIS) data in assessing soil moisture was investigated in this region. The 16-day composite MODIS Vegetation Index product (MOD13A2) and 8-day composite MODIS temperature product (MOD11A2) were used to calculate the TVDI. Correlation and regression analysis was carried out to relate the TVDI against in-situ soil moisture measurements data during the main growth stages of winter wheat/summer maize. The results show that a significantly negative relationship exists between the TVDI and in-situ measurements at different soil depths, but the relationship at 10–20 cm depth (R ²?=?0.43) is the closest. The spatial and temporal patterns in the TVDI were also analysed. The temporal evolution of the retrieved soil moisture was consistent with crop phenological development, and the spatial distribution of retrieved soil moisture accorded with the distribution of precipitation during the whole crop growing seasons. The TVDI index was shown to be feasible for monitoring the surface soil moisture dynamically during the crop growing seasons in the HHH plain.     

Application of the Exp-function method to the (2+1)-dimensional Boiti–Leon–Pempinelli equation using symbolic computation

This paper deals with the so-called Exp-function method for studying a particular nonlinear partial differential equation (PDE): the (2+1)-dimensional Boiti–Leon–Pempinelli equation. The method is constructive and can be carried out in a computer with the aid of a computer algebra system. The obtained generalized solitary wave solutions contain more arbitrary parameters compared with the earlier works, and thus, they are wider. This means that our method is effective and powerful for constructing exact and explicit analytic solutions to nonlinear PDEs.     

The Perspective Theory of Zong Bing in the 5~(th) Century of China

1 Introduction The perspective theory, a very important division of mathematics, geometry and technical drawing, is also called central perspective theory in engineering technology. Its appearance and development are closely related to human being抯 knowledge and practice in drawing and architecture. Actually, peoples understanding and knowledge of perspective theory may date as far back as the rock paintings in ancient times. No matter in the rock paintings of Mount Yin in Inner Mongol…     

The addition of stripes (a version of the ‘horizontal-vertical illusion’) increases foot clearance when crossing low-height obstacles

Trips over obstacles are one of the main causes of falling in older adults, with vision playing an important role in successful obstacle negotiation. We determined whether a horizontal-vertical illusion, superimposed onto low-height obstacles to create a perceived increase in obstacle height, increased foot clearances during obstacle negotiation thus reducing the likelihood of tripping. Eleven adults (mean ± 1?SD: age 27.3 ± 5.1 years) negotiated obstacles of varying heights (3, 5, 7 cm) with four different appearance conditions; two were obstacles with a horizontal-vertical illusion (vertical stripes of different thickness) superimposed on the front, one was a plain obstacle and the fourth a plain obstacle with a horizontal black line painted on the top edge. Foot clearance parameters were compared across conditions. Both illusions led to a significant increase in foot clearance when crossing the obstacle, compared to the plain condition, irrespective of obstacle height. Superimposing a horizontal-vertical illusion onto low-height obstacles can increase foot clearance, and its use on the floor section of a double-glazing door frame for example may reduce the incidence of tripping in the home.

Practitioner Summary: Low-height obstacles such as the floor section of a double-glazing door frame are potential tripping hazards. In a gait lab-based study we found that a horizontal-vertical illusion superimposed onto low-height obstacles led to significantly higher foot clearances; indicating their potential as a useful safety measure.     

Remote sensing of the terrestrial environment using middle infrared radiation (3.0–5.0 µm)

The middle infrared (MIR) spectral region, between 3.0 and 5.0?µm in the electromagnetic spectrum, features a myriad of atmospheric windows. The favourable atmospheric penetration of electromagnetic radiation at MIR wavelengths has been readily noted. To exploit this atmospheric window, there have been several remote sensing instruments acquiring radiation from the terrestrial environment. However, these data remain under-utilized for terrestrial environmental studies. The principal reason for this is the hybrid nature of this spectral region, as it comprises a combination of both reflected and emitted radiation during daytime measurement. Despite this, there are many attributes of the MIR spectral region that should encourage its use. Studies focusing on a wide range of terrestrial environment characteristics using MIR radiation have advocated that these data be used. Moreover, there has been a progressive maturation of the methods for processing the radiation acquired by instruments in the MIR spectral region, allowing the informed use of the unique information provided by this part of the spectrum. In particular, these methods have allowed the retrieval of MIR reflectance from the full MIR radiation acquired by a sensor and this information has been demonstrated to be particularly useful for the study of the terrestrial environment and its change. It would appear that the full potential of MIR radiation is unrealized. This paper is a review that aims to motivate and advise of future research using MIR radiation, and in particular MIR reflectance. The paper outlines the physical principles determining MIR radiation interactions with the terrestrial environment; reviews current status of processing methods of MIR radiation to retrieve MIR reflectance; and how the retrieved data have been used. In conclusion, future research priorities are suggested.     

The role of social media in higher education classes (real and virtual) – A literature review

The ubiquity of social media (e.g., Facebook, Twitter) is no more apparent than at the university. Social media are increasingly visible in higher education settings as instructors look to technology to mediate and enhance their instruction as well as promote active learning for students. Many scholars argue for the purposeful integration of social media as an educational tool. Empirical evidence, however, has lagged in supporting the claim. Most of the existing research on the utility and effectiveness of social media in the higher education class is limited to self-reported data (e.g., surveys, questionnaires) and content analyses. This paper summarizes the scholarly writings as well as reviews the findings of empirical investigations. Some limitations are discussed, and future areas of research are proposed.     

A bibliometric retrospective of the Journal Computers in Human Behavior (1991–2015)

This study aims to create a bibliometric profile of the Journal Computers in Human Behavior employing bibliometric analysis, bibliometric mapping and thematic analysis to identify its document types, the dynamics and trends of research literature production, impact factor, most cited articles, and large contributing institutions and countries. Additionally, the authors were interested in finding the established patterns of cooperation among countries and institutions and the most productive research themes and their evolution through time. We were also interested in finding out if there are any sleeping beauties among articles published in the Journal. The study revealed a positive trend of scientific literature production and that the average number of references is increasing contrary to the number of pages per publication, which is decreasing, although it has remained stable in recent years. The most productive countries and institutions are from the United States, and the majority of the literature production is done by economically and scientifically fit and well developed countries. The identified research themes correspond with the Journal's aims and scope. The rising number of publications, increasing number of citations and, consequently, the Journal impact factor, together with the existence of sleeping beauties, shows that the editorial policy is well thought out and future oriented.     

First observations of CO2 absorption spectra recorded in 2005 using an airship-borne FTS (GOSAT TANSO–FTS BBM) in the SWIR spectral region

This article describes the results of a field experiment performed to confirm the feasibility of measuring the solar spectra absorbed by carbon dioxide (CO₂) using a short wavelength infrared Fourier transform spectrometer (SWIR-FTS) installed onboard an airship. These airship-borne observations, conducted on 7 April 2005, represent the first aircraft-borne spectroscopic experiment on greenhouse gases (GHGs) in Japan and were performed as part of the Greenhouse Gases Observing Satellite (GOSAT) project. To develop and demonstrate an effective retrieval algorithm to derive CO₂ column amounts from spectroscopic observations, ground-surface scattered solar absorption spectra were observed by SWIR-FTS installed onboard the airship. This instrument is a breadboard model (BBM) of the Thermal and Near-infrared Sensor for Carbon Observation (TANSO) of GOSAT, which was successfully launched on 23 January 2009. The spectra of CO₂ observed using the BBM were compared with the simulated spectra calculated by a radiative transfer code based on airship-borne in situ measurement data, which were obtained at the time of FTS measurements. The two sets of spectra are in agreement within 5%, and we identified solutions to several technical problems related to the FTS instrument, thereby improving the signal-to-noise ratio (SNR).     

Assessment of the impact of coastal reclamation activities on seagrass meadows in Sungai Pulai estuary,Malaysia, using Landsat data (1994–2017)

Seagrass meadows play a critical role in supporting coastal biodiversity and in providing food and habitats for other marine organisms but are continuously threatened by human activities, such as coastal reclamation in the maritime countries. The Sungai Pulai estuary harbours mangroves, mudflats, and shoals with one of the Malaysia’s largest seagrass meadow (Merambong, Tanjung Adang, and Tanjung Laut) in Johor, Malaysia. This study assessed the environmental impact of coastal reclamation activities based on Landsat imagery (1994–2017) through mapping cover and distribution changes of those seagrass meadows by using a previously developed image enhancement technique with further improvement in the classification scheme (87% overall accuracy). The image-difference maps showed changes in seagrass meadows and mudflat cover with the extension of reclaimed land. Some seagrass meadows experienced large-scale changes, and coastal reclamation activities have been suggested as main factors responsible for habitat degradation, reduction in coverage, and total loss due to physical damage and excessive sedimentation. Sufficient protection of on-site construction materials is essential if coastal areas are to conserve seagrass meadows. This Landsat-based image classification approach should help the coastal manager to map seagrass meadows and to monitor the environmental impact of reclamation activities with a large spatio-temporal scale.