Given uncertainty in the processes involved in polar amplification, elucidating the role of poleward heat and moisture transport is crucial. The Polar Amplification Model Intercomparison Project (PAMIP) permits robust separation of the effects of sea ice loss from sea surface warming under climate change. We utilize a moist isentropic circulation framework that accounts for moisture transport, condensation, and eddy transport, in order to analyze the circulation connecting the mid‐latitudes and the Arctic. In PAMIP's atmospheric general circulation model experiments, prescribed sea ice loss reduces poleward heat transport (PHT) by warming the returning moist isentropic circulation at high latitudes, while prescribed warming of the ocean surface increases PHT by strengthening the moist isentropic circulation. Inter‐model spread of PHT into the Arctic reflects the tug‐of‐war between sea‐ice and surface‐warming effects.

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Rapid sea ice retreat has been extensively observed in the Canada Basin over the past several decades (F. McLaughlin et al., 2011). The increased sea ice melt and river runoff that has collected toward the center of the anticyclonic (convergent)

Evidence from models and observations suggests that the vertical distribution of entropy in the extratropical troposphere reflects the horizontal distribution of entropy at the surface. This isentropic linkage, which is accomplished through moist isentropic mass transport driven by extratropical waves, becomes more apparent when the effect of latent heat release by condensing moist parcels is accounted for. This study focuses on the stratification of the Arctic troposphere, which is connected by moist isentropes to the midlatitude surface. A relatively simple moist general circulation model without radiative feedbacks involving water vapor or clouds is used to study the linkage between the midlatitude surface and the Arctic midtroposphere. Zonally symmetric midlatitude thermal perturbations switched on at the surface drive a moist potential temperature response in the Arctic midtroposphere with a lag of about 2 weeks. This response increases the gross moist vertical stability in the Arctic while generally decreasing it, or increasing it only weakly, in the midlatitudes. The moist isentropic streamfunction is shifted poleward owing to the poleward entropy flux response and is shifted upward (i.e., to higher entropy) owing to the zonal-mean entropy response. The results suggest a potential novel mechanism by which the midlatitudes might influence polar lapse rates and their associated radiative feedbacks.

Phosphate deposits are the main source of raw materials used by the phosphate fertilizer industry and, in recent years, they have also been considered as potential sources of rare earth elements (REEs) and fluorine (F). Based on 160 portable XRF (pXRF) measurements taken on 32 pulps of naturally occurring phosphate rocks from the Fernie Formation (British Columbia, Canada) with a representative range of P and REE concentrations, the pXRF analyser was able to provide data with acceptable precision, accuracy, and excellent coefficients of determination (r 2 ≥ 0.85) relative to the laboratory data for Ba, Mo, Y, Sr, U, Rb, Zn, Fe, Ca, P, Si and S. Results with coefficients of determination of 0.5 ≤ r 2 < 0.85 between the pXRF and laboratory-derived datasets were achieved for Nd, Ce, La, Zr, W, and Al. From an exploration geologist’s point of view, P and Fe were measured accurately enough by pXRF using the factory-set calibration. Portable XRF analysis for Nd, Pr, Ce, La, Ba, Mo, Zr, Y, Sr, U, Rb, Zn, Ca, K, Al, Si and S had to be recalibrated relative to laboratory results. Using factory pXRF settings, light REEs (La, Ce, Pr, Nd) were subject to systematic overestimation relative to laboratory results whereas Y was subject to systematic underestimation. This study presents the first stage of an orientation survey (pulp analyses) for sedimentary phosphate occurrences containing REEs in southeastern British Columbia. If sample preparation (to pulps) and field recalibration are carried out, pXRF can identify zones of phosphate rocks enriched in REEs, and delimit zones with unacceptable levels of deleterious elements, such as uranium.