scholarly journals WATER TEMPERATURE VARIATIONS WITHIN A MAJOR RIVER SYSTEM

1975 ◽  
Vol 6 (3) ◽  
pp. 155-169 ◽  
Author(s):  
K. SMITH
Keyword(s):  
Water Temperature ◽  
Air Temperature ◽  
Stream Flow ◽  
River System ◽  
Daily Maximum ◽  
Main Stream ◽  
Temperature Variations ◽  
River Temperature ◽  
Air Temperatures ◽  
Storm Rainfall

This paper examines the relationships between river water temperature, air temperature and stream flow measured continuously for one year at four sites along the main stream of the river Tees in northern England. Maximum and minimum river temperatures were found to correlate fairly closely with equivalent air temperatures at each site, but some emphasis was placed on the effects of hydrological factors on water temperature variations within the 818 km2 basin. The range of water temperature fluctuations was shown to increase upstream and the highest river maxima were also recorded in the upper reaches of the river, owing to the relatively low volume of discharge. On a shorter time scale, stream flow was also found to exert an important influence on river temperature during snowmelt and peak flow events arising from storm rainfall. A multiple regression analysis indicated that air temperature and stream flow together accounted for up to 85 % of the variation of daily maximum and minimum river temperatures in summer.

Skinfolds and resting heat loss in cold air and water: temperature equivalence

1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Indirect Calorimetry ◽  
Cold Water ◽  
Heat Conductance ◽  
Air Temperatures ◽  
Body Core ◽  
Male Subjects

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
Water Temperature ◽  
Stream Flow ◽  
River System ◽  
Lunar Phase ◽  
Upstream Migration ◽  
Potomac River ◽  
River Drainage ◽  
Thermal Refuge ◽  
American Eels ◽  
Atlantic Coastal

<em>Abstract.—</em>Yellow-phase American eels <em>Anguilla rostrata </em>migrate upstream extensively in Atlantic coastal river systems. However, few studies have focused on movements of large yellow American eels near dams in upper watersheds of Atlantic coastal rivers. We examined relationships between environmental variables (stream flow, water temperature, and lunar phase) and movements of radio-tagged yellow American eels (518–810 mm TL) near Millville hydroelectric dam in the lower Shenandoah River drainage of the upper watershed of the Potomac River system, West Virginia. Movements of yellow American eels differed seasonally. Water temperature and stream flow were associated with upstream migration during spring. Downstream movements during fall coincided with decreasing water temperatures and darker nights near the new moon. Eels overwintered in thermal refuge areas near tributary mouths. Localized irregular upstream and downstream movements during summer occurred near dusk and dawn and possibly reflected crepuscular foraging. Our study in the Potomac River drainage suggests the need for upstream eel passage at hydroelectric facilities when spring water temperatures exceed 15°C.

INFLUENCE OF TEMPERATURE AND HUMIDITY ON THE EMERGENCE BEHAVIOUR OF ANAX JUNIUS (ODONATA: AESHNIDAE)

1973 ◽  
Vol 105 (7) ◽  
pp. 975-984 ◽  
Author(s):  
Robert Trottier
Keyword(s):  
Relative Humidity ◽  
Water Temperature ◽  
Air Temperature ◽  
Water Surface ◽  
Average Speed ◽  
Anax Junius ◽  
Air Temperatures ◽  
Stage 4 ◽  
Temperature And Humidity ◽  
Three Stages

AbstractEmergence from the water of Anax junius Drury normally occurred after sunset. The onset was affected independently by water temperature and air temperature; low water temperature and high air temperature delayed the onset of emergence. In the field, the net vrtical distance travelled above the water, before ecdysis, was positively correlated with air temperature. In the laboratory, the vertical distance travelled above the water was greatest when air and water temperatures were approximately the same. The average speed of climbing to the first resting position above the water surface was faster at high than low water temperature, but the average speed of climbing from there to the final position, where ecdysis occurred, was reduced due to the effects of air temperature and humidity. Air temperatures below 12.6 °C were found to retard ecdysis and larvae returned to the water and emerged early the following day making the final process of emergence and ecdysis diurnal instead of nocturnal. The duration of ecdysis was shorter at high than low air temperatures and only the first three stages, as arbitrarily defined, were longer at low than high relative humidity; stage 4, shortened with low relative humidity. This study shows that A. Junius, emerging from the water is affected at first by the temperature experienced when submerged, but it becomes gradually and cumulatively affected by air temperature and humidity while climbing to the ecdysial position and moulting.

scholarly journals Analyses of the Zagreb Grič observatory air temperatures indices for the period 1881 to 2017

2018 ◽  
pp. 67-85 ◽  
Author(s):  
Ognjen Bonacci ◽  
Tanja Roje Bonacci
Keyword(s):  
Time Series ◽  
Air Temperature ◽  
Partial Sums ◽  
Daily Maximum ◽  
Absolute Maximum ◽  
Absolute Minimum ◽  
Air Temperatures ◽  
Temperature Regimes ◽  
Urban Heat ◽  
Maximum Temperatures

The paper studies time series of characteristic (minimum, mean, and maximum) daily, monthly, and yearly air temperatures measured at the Zagreb Grič Observatory in the period from 1 Jan. 1881 to 31 Dec. 2017. The following five air temperatures indices (ATI) are analysed: (1) absolute minimum yearly, monthly, and daily; (2) mean yearly, monthly, and daily minimum; (3) average mean yearly, monthly, and daily; (4) mean yearly, monthly, and daily maximum; (5) absolute maximum yearly, monthly, and daily. Methods of Rescaled Adjusted Partial Sums (RAPS), regression and correlation analyses, F-tests, and t-tests are used in order to describe changes in air temperature regimes over 137 years. Using the RAPS method the five analysed yearly ATI time series durations of 137 years were divided into two sub-periods. The analyses made in this paper showed that warming of minimum air temperatures started in 1970, mean air temperatures in 1988, and maximum air temperatures in 1998. Results of t-tests show an extreme statistically significant jump in the average air-temperature values in the second (recent time) sub-periods. Results of the t-tests of monthly temperatures show statistically significant differences between practically all five pairs (except in two cases) of analysed monthly ATI subseries for the period from January to August. From September to December the differences for most of pairs (except in six cases) of the analysed monthly ATI subseries are not statistically significant. It can be concluded that the urban heat island influenced the increase in recent temperatures more strongly than global warming. It seems that urbanisation firstly and chiefly influenced the minimum temperatures, as well as that Zagreb’s urbanisation had a bigger impact on minimum temperatures than on maximums. Increasing trend in time series of maximum temperatures started 20 years later.

scholarly journals Anthropogenic Influence on the Rhine water temperatures

2019 ◽  
Author(s):  
Alex Zavarsky ◽  
Lars Duester
Keyword(s):  
River Water ◽  
Air Temperature ◽  
Nuclear Power ◽  
Important Variable ◽  
Anthropogenic Influence ◽  
River Temperature ◽  
Air Temperatures ◽  
Long Term Trend ◽  
River Water Temperature

Abstract. River temperature is an important parameter for water quality and an important variable for physical, chemical and biological processes. River water is also used by production facilities as cooling agent.We introduce a new way of calculating a catchment-wide air temperature and regressing river temperature vs air temperatures. As a result the meteorological influence and the anthropogenic influence can be studied separately. We apply this new method at four monitoring stations (Basel, Worms, Koblenz and Cologne) along 5 the Rhine and show that the long term trend (1979–2018) of river water temperature is, next to the increasing air temperature, mostly influenced by decreasing nuclear power production. Short term changes on time scales

scholarly journals Long-Term Winter Inversion Properties in a Mountain Valley of the Western United States and Implications on Air Quality

2015 ◽  
Vol 54 (12) ◽  
pp. 2339-2352 ◽  
Author(s):  
S.-Y. Simon Wang ◽  
Lawrence E. Hipps ◽  
Oi-Yu Chung ◽  
Robert R. Gillies ◽  
Randal Martin
Keyword(s):  
Air Quality ◽  
Air Temperature ◽  
Daily Maximum ◽  
Horizontal Distance ◽  
Climate Conditions ◽  
Air Temperatures ◽  
Narrow Valley ◽  
Northern Utah ◽  
Temperature Inversions

AbstractBecause of the geography of a narrow valley and surrounding tall mountains, Cache Valley (located in northern Utah and southern Idaho) experiences frequent shallow temperature inversions that are both intense and persistent. Such temperature inversions have resulted in the worst air quality in the nation. In this paper, the historical properties of Cache Valley’s winter inversions are examined by using two meteorological stations with a difference in elevation of approximately 100 m and a horizontal distance apart of ~4.5 km. Differences in daily maximum air temperature between two stations were used to define the frequency and intensity of inversions. Despite the lack of a long-term trend in inversion intensity from 1956 to present, the inversion frequency increased in the early 1980s and extending into the early 1990s but thereafter decreased by about 30% through 2013. Daily mean air temperatures and inversion intensity were categorized further using a mosaic plot. Of relevance was the discovery that after 1990 there was an increase in the probability of inversions during cold days and that under conditions in which the daily mean air temperature was below −15°C an inversion became a certainty. A regression model was developed to estimate the concentration of past particulate matter of aerodynamic diameter ≤ 2.5 μm (PM2.5). The model indicated past episodes of increased PM2.5 concentrations that went into decline after 1990; this was especially so in the coldest of climate conditions.

Imprints of evaporation and vegetation type in diurnal temperature variations

2020 ◽  
Author(s):  
Annu Panwar ◽  
Axel Kleidon ◽  
Maik Renner
Keyword(s):  
Solar Radiation ◽  
Surface Temperature ◽  
Air Temperature ◽  
Geophysical Research ◽  
Evaporative Fraction ◽  
Temperature Variations ◽  
Diurnal Temperature ◽  
Air Temperatures ◽  
Warming Rate ◽  
Surface Temperature Warming

&lt;p&gt;Diurnal temperature variations are strongly shaped by the absorption of solar radiation, but evaporation, or the latent heat flux, also plays an important role. Generally, evaporation cools, but its relation to diurnal temperature variations is unclear. This study investigates the diurnal response of surface and air temperatures to solar radiation and how evaporation and vegetation modify their response. We used the warming rate of temperature to absorbed solar radiation in the morning under clear-sky conditions and evaluated how the warming rates change for different evaporative fractions. Results for 51 FLUXNET sites show that air temperature carries very weak imprints of evaporation across all vegetation types. However, surface temperature warming rates of short vegetation decrease significantly by ~23 x 10&lt;sup&gt;-3&lt;/sup&gt; K/W m&lt;sup&gt;-2&lt;/sup&gt; from dry to wet conditions. Contrarily, warming rates of surface and air temperatures are similar at forest sites and carry literally no imprints of evaporation. We explain these contrasting patterns with a surface energy balance model. The model reveals a strong sensitivity of the warming rates to evaporative fraction and aerodynamic conductance. However, for the large aerodynamic conductance, the sensitivity to the evaporative fraction is strongly reduced. We then show that in addition to the higher aerodynamic conductance of forests, imprints of evaporation in the warming rate of surface temperature are reduced by 50% through an enhanced aerodynamic conductance under dry conditions. This contribution is comparatively weak (28%) for short vegetation. These findings have implications for the interpretation of land-atmosphere interactions and the roles of moisture limitation and vegetation on diurnal maximum temperatures, which is of key importance for ecological functioning. We conclude that surface temperature warming rate is a promising predictor of evaporation for short vegetation. These findings are in agreement with our previous study (Panwar et al., 2019) where the weaker response of air temperature to the evaporative fraction is explained by the larger growth of the boundary layer on drier days. In forests, however, the diurnal variation in temperatures is governed by their aerodynamic properties resulting in no imprint of evaporation in diurnal temperature variations.&lt;/p&gt;&lt;p&gt;Reference: Panwar, A., Kleidon, A. and Renner, M.: Do Surface and Air Temperatures Contain Similar Imprints of Evaporative Conditions?, Geophysical Research Letters, 46(7), 3802&amp;#8211;3809, doi:10.1029/2019GL082248, 2019.&lt;/p&gt;

scholarly journals Influence of air temperature on a glacier’s active-layer temperature

2006 ◽  
Vol 43 ◽  
pp. 285-291 ◽  
Author(s):  
V. Zagorodnov ◽  
O. Nagornov ◽  
L.G. Thompson
Keyword(s):  
Active Layer ◽  
Air Temperature ◽  
Seasonal Temperature ◽  
Temperature Variations ◽  
Surface Conditions ◽  
Tropical Glaciers ◽  
Air Temperatures ◽  
Screen Level ◽  
The Mean

AbstractSeasonal temperature variations occur in the glacier layer about 15–20 m below the surface, while at greater depths the glacier temperature depends on the long-term surface conditions. It is generally accepted that for glaciers without surface melting the temperature at 10 m depth (T10) is close to the mean annual air temperature at standard screen level (Ta), i.e. T10 =Ta. We found that this relationship is not valid for Ta above –17˚C and below –55˚C. The goal of our investigation is to find a better temperature transfer function (TTF) between Ta and temperature at the boundary of the active layer in accumulation areas of polar and tropical glaciers. Low-precision T10 temperatures from boreholes, obtained at 41 sites, are compared with air temperatures (Ta) measured in the vicinity of these sites for at least a 1 year period. We determine that when Ta falls into the temperature range –60 to –7˚C, empirical values can be approximated as T10 = 1:2Ta + 6:7. Analysis of these data suggests that high T10 occurs in the areas of the glacier that collect meltwater.

scholarly journals A Temperature Index Model to Estimate Long-term Freeze-risk of Satsuma Mandarins Grown on the Northern Coast of the Gulf of Mexico

2005 ◽  
Vol 130 (4) ◽  
pp. 500-507 ◽  
Author(s):  
R.C. Ebel ◽  
B.L. Campbell ◽  
M.L. Nesbitt ◽  
W.A. Dozier ◽  
J.K. Lindsey ◽  
...  
Keyword(s):  
Air Temperature ◽  
Cold Hardiness ◽  
Management Practices ◽  
Rating Scale ◽  
Daily Maximum ◽  
Northern Coast ◽  
Freeze Injury ◽  
Air Temperatures ◽  
The Difference

Estimates of long-term freeze-risk aid decisions regarding crop, cultivar, and rootstock selection, cultural management practices that promote cold hardiness, and methods of freeze protection. Citrus cold hardiness is mostly a function of air temperature, but historical weather records typically contain only daily maximum (Tmax) and minimum (Tmin) air temperatures. A mathematical model was developed that used Tmax and Tmin to estimate air temperature every hour during the diurnal cycle; a cold-hardiness index (CHI500) was calculated by summing the hours ≤10°C for the 500 h before each day; and the CHI500 was regressed against critical temperatures (Tc) that cause injury. The CHI500 was calculated from a weather station located within 0.1 km of an experimental grove and in the middle of the satsuma mandarin (Citrus unshiu Marc.) industry in southern Alabama. Calculation of CHI500 was verified by regressing a predicted CHI500 using Tmax and Tmin, to a measured CHI500 calculated using air temperatures measured every hour for 4 winter seasons (1999-2003). Predicted CHI500 was linearly related to measured CHI500 (r2 = 0.982). However, the slope was a little low such that trees with a CHI500 = 400, near the maximum cold-hardiness level achieved in this study, had predicted Tc that was 0.5 °C lower than measured Tc. Predicted and measured Tc were similar for nonhardened trees (CHI500 = 0). The ability of predicted Tc to estimate freeze injury was determined in 18 winter seasons where freeze injury was recorded. During injurious freeze events, predicted Tc was higher than Tmin except for a freeze on 8 Mar. 1996. In some freezes where the difference in Tc and Tmin was <0.5 °C there were no visible injury symptoms. Injury by the freeze on 8 Mar. 1996 was due, in part, to abnormally rapid deacclimation because of defoliation by an earlier freeze on 4-6 Feb. the same year. A freeze rating scale was developed that related the difference in Tc and Tmin to the extent of injury. Severe freezes were characterized by tree death (Tc - Tmin > 3.0 °C), moderate freezes by foliage kill and some stem dieback (1.0 °C ≤ Tc - Tmin ≤ 3.0 °C), and slight freezes by slight to no visible leaf injury (Tc - Tmin < 1.0 °C). The model was applied to Tmax and Tmin recorded daily from 1948 through 2004 to estimate long-term freeze-risk for economically damaging freezes (severe and moderate freeze ratings). Economically damaging freezes occurred 1 out of 4 years in the 56-year study, although 8 of the 14 freeze years occurred in two clusters, the first 5 years in the 1960s and 1980s. Potential modification of freeze-risk using within-tree microsprinkler irrigation and more cold-hardy cultivars was discussed.

scholarly journals Anthropogenic influence on the Rhine water temperatures

2020 ◽  
Vol 24 (10) ◽  
pp. 5027-5041
Author(s):  
Alex Zavarsky ◽  
Lars Duester
Keyword(s):  
Water Temperature ◽  
River Water ◽  
Air Temperature ◽  
Nuclear Power ◽  
Important Variable ◽  
Anthropogenic Heat ◽  
River Rhine ◽  
River Temperature ◽  
Time Lagged ◽  
River Water Temperature

Abstract. River temperature is an important parameter for water quality and an important variable for physical, chemical and biological processes. River water is also used by production facilities as cooling agent. We introduced a new way of calculating a catchment-wide air temperature using a time-lagged and weighed average. Regressing the new air temperature vs. river water temperature, the meteorological influence and the anthropogenic heat input could be studied separately. The new method was tested at four monitoring stations (Basel, Worms, Koblenz and Cologne) along the river Rhine and lowered the root mean square error of the regression from 2.37 ∘C (simple average) to 1.02 ∘C. The analysis also showed that the long-term trend (1979–2018) of river water temperature was, next to the increasing air temperature, mostly influenced by decreasing nuclear power production. Short-term changes in timescales < 5 years were connected with changes in industrial production. We found significant positive correlations for the relationship.

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