## 1 Introduction  
The need to better understand and predict future carbon-climate interactions makes the assessment of biosphere-atmosphere carbon exchange for the various biomes of the planet a critical topic for the scientific community and policy-makers [1]. There is growing interest in assessing biospheric carbon storage with the hope that management regimes can optimize carbon sequestration. Also, soil processes play an important role in global climate change as soils have the potential to act as a net sink for CO\({}_{2}\) due to the large amount of carbon currently stored in soil organic matter [2; 3]. However, biosphere-atmosphere carbon fluxes are inherently dynamic, affected by short-term disturbance and weather events, making evaluation and prediction of carbon storage and climate feedbacks challenging. While much attention has been given to forests for their large feedback and carbon sequestration [4], the carbon storage potential of other biomes has been less thoroughly considered, even though many non-forest biomes cover large areas, contribute measurably to overall biospheric carbon uptake and storage, and provide economically important ecosystem goods and services. Rangelands occupy close to 50% of the world's land area [5]. They are defined as lands where indigenous or introduced vegetation is grazed or has the potential to be grazed and are generally considered and managed as natural ecosystems [6]. Rangelands include natural grasslands, savannas, shrublands, deserts, tundra, alpine communities, marshes, and wet meadows [7]. The grassland or prairie biome is particularly important in Alberta, as the Grassland Natural Region covers 14.4% of the province [8]. The Dry Mixedgrass Natural Subregion accounts for 47.5% of the Grassland Natural Region area, and thus represents 7% of the area of Alberta province [9]. Grassland provides a number of important services including carbon sequestration and livestock forage. The capacity of grassland ecosystems to sequester carbon is a leading factor in the consideration of policies and practices that maximize carbon storage without compromising managers' profits [10]. The carbon sequestration of a grassland can vary considerably from year to year since it is influenced both by natural and anthropogenic factors such as temperature, rainfall, species composition, nutrient and water availability, light, grazing pressure and agricultural practices [11; 12]. Together, these factors make grassland carbon exchange responsive to climate change [13; 14; 15], and drive interest in monitoring grassland ecosystem responses for the purpose of developing optimal management regimes. Historically, most attempts to assess ecosystem carbon storage have been based on field sampling of above- and below-ground biomass and carbon, which requires considerable investments in time and personnel [16], and may not capture the temporal dynamics in response to changing conditions. Ecosystem carbon dynamics have been modeled using different input parameters including climate [17; 18] or soil and nutrient availability [19; 20]. However, models often lack spatially or temporally sufficient data inputs, so may not take into account all ecosystem dynamics and interactions. Significant progress in understanding ecosystem dynamics has been accomplished using the eddy covariance (EC) technique, which quantifies carbon and water vapor fluxes between the biosphere and the atmosphere [21]. This technique has been successfully applied to estimate carbon fluxes in grassland ecosystems [22; 23]. Nevertheless, the EC technique is expensive, subject to data gaps, and limited to relatively flat, large landscape regions, so cannot offer universal sampling of fluxes for all locations. Remote sensing and proximal optical sampling methods can provide cost-effective, uniform sampling under conditions where eddy covariance techniques would be impractical.