The very large number of human thermal climate indices that have been proposed over the past 100 years or so is a manifestation of the perceived importance within the scientific community of the thermal environment and the desire to quantify it. Schemes used differ in approach according to the number of variables taken into account, the rationale employed, the relative sophistication of the underlying body-atmosphere heat exchange theory and the particular design for application. They also vary considerably in type and quality, as well as in several other aspects. Reviews appear in the literature, but they cover a limited number of indices. A project that produces a comprehensive documentation, classification and overall evaluation of the full range of existing human thermal climate indices has never been attempted. This paper deals with documentation and classification. A subsequent report will focus on evaluation. Here a comprehensive register of 162 thermal indices is assembled and a sorting scheme devised that groups them according to eight primary classification classes. It is the first stage in a project to organise and evaluate the full range of all human thermal climate indices. The work, when completed, will make it easier for users to reflect on the merits of all available thermal indices. It will be simpler to locate and compare indices and decide which is most appropriate for a particular application or investigation.

Numerous human thermal climate indices have been proposed. It is a manifestation of the perceived importance of the thermal environment within the scientific community and a desire to quantify it. Schemes used differ in approach according to the number of variables taken into account, the rationale employed, and the particular design for application. They also vary considerably in type and quality, method used to express output, as well as in several other aspects. In light of this, a three-stage project was undertaken to deliver a comprehensive documentation, classification, and overall evaluation of the full range of existing human thermal climate indices. The first stage of the project produced a comprehensive register of as many thermal indices as could be found, 165 in all. The second stage devised a sorting scheme of these human thermal climate indices that grouped them according to eight primary classification categories. This, the third stage of the project, evaluates the indices. Six evaluation criteria, namely validity, usability, transparency, sophistication, completeness, and scope, are used collectively as evaluation criteria to rate each index scheme. The evaluation criteria are used to assign a score that varies between 1 and 5, 5 being the highest. The indices with the highest in each of the eight primary classification categories are discussed. The work is the final stage of a study of the all human thermal climatic indices that could be found in literature. Others have considered the topic, but this study is the first detailed, genuinely comprehensive, and systematic comparison. The results make it simpler to locate and compare indices. It is now easier for users to reflect on the merits of all available thermal indices and decide which is most suitable for a particular application or investigation.

We used the concept of growing degree-days (GDD) as a measure of the agricultural potential of climate on a regional scale in the southern part of the Russian Far East, the climate of which is characterized by thermal extremes. Daily maximum and minimum air temperatures were used to calculate GDD at 17 locations using threshold base air temperatures of 0, 5, 10 and 15°C, with a high-temperature threshold cut-off of 30°C. GDD increased from north to south in the study area, but the mean GDD varied considerably from one location to another. Marginal thermal conditions were observed in the north, both in the elevated areas and in the coastal regions. There was a high correlation between GDD and mean monthly temperature for the growing season from May to September (T59), such that the latter can be used as a proxy for GDD, which has implications for agricultural management. GDD and T59 had an upward trend over the period for the study region as a whole. The most significant upward trend was observed for GDD0, while results for GDD15 exhibit little or no trend.KEY WORDS: Growing degree-days · Climate change · Spatial and temporal analysis · Russian Far East · Climate and agriculture · Agro-climate indices · Biologically active temperature Resale or republication not permitted without written consent of the publisherClim Res 42: [143][144][145][146][147][148][149][150][151][152][153][154] 2010 climatic indices used to quantify the rate of development of crops have evolved from this. They include simple heat units based on the accumulation of daily mean temperatures above a certain threshold temperature during growing period (Wiggans 1956, Brown 1960, Wang 1960, Baskerville & Emin 1969, Chen 1973. Others are: the sum of effective temperatures (Chirkov 1965, Gordeev et al. 2006; effective degrees (Gilmore & Rogers 1958); the accumulated heat unit (Mederski et al. 1973); growing degree units (Darby & Lauer 2002); P-days, which is a heat unit for the growth and development of potatoes (Sands et al. 1979); corn heat units, used to define the relationship between temperature and the development of corn hybrids (Smith et al. 1982, Bootsma 1994, Dwyer et al. 1999, Bootsma et al. 2004; the general thermal index, developed from statistically fitted maize development temperature response functions for the vegetative and grain-filling periods (Dwyer et al. 1999); and photothermal units (McMaster & Smika 1988).There have been other approaches. One method calculates sums of positive temperatures over a period above a given threshold temperature (T base ), referred to as active temperatures for the growth period starting from the date of the onset of spring (e.g. Davitaya 1965, Kelchevskaya 1971, Karing et al. 1999, Gordeev et al. 2006. The sum of biologically active temperatures (T ac ) is given as:( 1) where T i is mean daily temperature (°C) and i = 1, 2…n is the number of days with mean temperature above the respective threshold or base temperature (T base ), marking the start of the growing season (Table 1). The ...