An improved hemispherical photography model for stream surface shortwave radiation estimations in a central U.S. hardwood forest

Bulliner, E. A.; Hubbart, Jason A.

doi:10.1002/hyp.9524

Cited by 13 publications

(6 citation statements)

References 29 publications

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“…Overall, results show that solar radiation (net short‐wave radiation) remains a dominant heat gain, even in small‐stream environments, with an average of 13.4 W m −2 for the summer (Table ). These results are consistent with previous studies (Webb and Zhang, ; Bulliner and Hubbart, ). For example, Webb and Zhang () showed solar radiation values of 11.6 W m −2 (Jackmoor Brook) and 10.4 W m −2 (Iron Mill Stream) within their small studied streams.…”

Section: Discussionsupporting

confidence: 94%

River evaporation, condensation and heat fluxes within a first-order tributary of Catamaran Brook (New Brunswick, Canada)

Caissie

2016

Hydrol. Process.

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Abstract:Stream temperature plays an important role in many biotic and abiotic processes, as it influences many physical, chemical and biological properties in rivers. As such, a good understanding of the thermal regime of rivers is essential for effective fisheries management and the protection aquatic habitats. Moreover, a thorough understanding of underlying physical processes and river heat fluxes is essential in the development of better and more adaptive water temperature models. Very few studies have measured river evaporation and condensation and subsequently calculated corresponding heat fluxes in small tributary streams, mainly because microclimate data (data collected within the stream environment) are essential and rarely available. As such, the present study will address these issues by measuring river evaporation and condensation in tributary 1 (Trib 1, a small tributary within Catamaran Brook) using floating minipans. The latent heat flux and other important fluxes were calculated. Results showed that evaporation was low within the small Trib 1 of Catamaran Brook, less than 0.07 mm day À1 . Results showed that condensation played an important role in the latent heat flux. In fact, condensation was present during 34 of 92 days (37%) during the summer, which occurred when air temperature was greater than water temperature by 4-6°C. Heat fluxes within this small stream showed that solar radiation dominated the heat gains and long-wave radiation dominated the heat losses.

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Section: Discussionsupporting

confidence: 94%

River evaporation, condensation and heat fluxes within a first-order tributary of Catamaran Brook (New Brunswick, Canada)

Caissie

2016

Hydrol. Process.

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“…The root mean square error and mean bias error ranged between 17 and 22, and −18 and −6 W m −2 , respectively, across the 14 sites. These errors are similar to those found in previous efforts to model above-stream net radiation from hemispherical photographs (Leach and Moore, 2010;Bulliner and Hubbart, 2013).…”

Section: Energy Balancesupporting

confidence: 88%

Winter stream temperature in the rain-on-snow zone of the Pacific Northwest: influences of hillslope runoff and transient snow cover

Leach

Moore

2014

Hydrol. Earth Syst. Sci.

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Abstract. Stream temperature dynamics during winter are less well studied than summer thermal regimes, but the winter season thermal regime can be critical for fish growth and development in coastal catchments. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two hypotheses were addressed by this study: (1) winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2) stream temperatures should be depressed during rain-on-snow events, compared to rain-on-bare-ground events, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. A reach-scale energy budget analysis of two winter seasons revealed that the advective energy input associated with hillslope runoff overwhelms vertical energy exchanges (net radiation, sensible and latent heat fluxes, bed heat conduction, and stream friction) and hyporheic energy fluxes during rain and rainon-snow events. Historical stream temperature data and modelled snowpack dynamics were used to explore the influence of transient snow cover on stream temperature over 13 winters. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 • C, regardless of air temperature. The stream energy budget modelling and historical analysis support both of our hypotheses. A key implication is that climatic warming may generate higher winter stream temperatures in the rain-on-snow zone due to both increased rain temperature and reduced cooling effect of snow cover.

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“…In GLA, analyzing the photos requires a threshold value to be determined by the user. Pixels darker than the threshold value are separated into "canopy, " and pixels lighter than this value are separated into "sky" [29]. Three parameters were selected, representing the transmitted gap light regime in the understory.…”

Section: Soil Sampling and Hemispherical Photographymentioning

confidence: 99%

Understory Flora in Relation to Canopy Structure, Soil Nutrients, and Gap Light Regime: a Case Study in Southern China

Ou¹,

Cao²,

Shen³

et al. 2015

Pol. J. Environ. Stud.

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To better understand the contribution of understory to biodiversity of a forest ecosystem, we examined the understory in stands of: (1) a Phyllostachys edulis (Moso bamboo) plantation, (2) a Cunninghamia lanceolata (Chinese fir) plantation and (3) a natural evergreen and deciduous broad-leaved mixed forest (natural mixed forest) in Mt. Mao'er in southern China, and the distribution and diversity of understory in relation to environmental conditions (overstory structure, soil nutrients, and gap light level). Soil samples were taken and analyzed in a laboratory for pH, organic matter (SOM), and total nitrogen (TN). Hemispherical photographs were taken using a Panasonic DMC-LX5 digital camera and analyzed using Gap Light Analyzer 2.0 software. Statistical methods, such as multi-response permutation procedure (MRPP), detrended correspondence analysis (DCA), Mantel test, and stepwise multiple linear regressions were used in this study. Canopy communities were significantly different in basal area (BA), density, and species richness but not Shannon diversity (H'). Soil variables differed in terms of soil pH and TN across the three canopy types; however, the light levels did not differ significantly. MRPP revealed significant differences in species composition of understory among the three forest types. DCA ordination separated sample plots into three groups corresponding to the three forest types. Multiple stepwise regressions showed that soil pH combined with SOM, Overstory-H′ and TTot could explain 99% of the variation in understory species richness, while Overstory-H' with Overstory-S, Density, and SOM could explain 92% of the variation in understory diversity. The results indicated that canopy structure together with soil nutrient were the best predictors of understory vegetation in the study area.

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An improved hemispherical photography model for stream surface shortwave radiation estimations in a central U.S. hardwood forest

Cited by 13 publications

References 29 publications

River evaporation, condensation and heat fluxes within a first-order tributary of Catamaran Brook (New Brunswick, Canada)

River evaporation, condensation and heat fluxes within a first-order tributary of Catamaran Brook (New Brunswick, Canada)

Winter stream temperature in the rain-on-snow zone of the Pacific Northwest: influences of hillslope runoff and transient snow cover

Understory Flora in Relation to Canopy Structure, Soil Nutrients, and Gap Light Regime: a Case Study in Southern China

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