Orographic precipitation: mesoscale modeling perspective

Summer 1998.Includes bibliographical references.This study demonstrates the utility of the Regional Atmospheric Modeling System (RAMS) in analyzing the distribution of precipitation along Alaska's Kenai Peninsula during the September 19-21, 1995 heavy precipitation and flood event. The model generated heavy precipitation over the coastal mountains, with lighter amounts at both lower elevations and to the lee of the windward barrier. The model precipitation was in reasonably good agreement with the limited set of observations. Included in this study are series of simulations that are designed to test the models sensitivity to initial values of wind speed, wind direction, moisture, and atmospheric stability. The results show that the areal and vertical distribution of model generated precipitation is quite sensitive to realistic perturbations in the initial fields, primarily as a result of the change in the vertical velocity structure of the model atmosphere. It is apparent that since most mountainous regions are also data sparse, initializing a model is a serious challenge. Large uncertainty in initial conditions as well as the highly nonlinear nature of the precipitation process, necessitates an ensemble approach to quantitative precipitation forecasting (QPF). Using 15 six hour model simulations an ensemble QPF is generated. The results indicate an order of magnitude variance in precipitation over the mountains, using perturbations that are within observational uncertainty. Since mesoscale models have adjustable grids, it is important to understand the relationship between grid interval, terrain resolution and model generated precipitation. Findings from this study suggest that as the grid interval decreases from 15 km to 10 km, precipitation increased by 33%. A further decrease in grid interval from 10 km to 5 km increased precipitation by an additional 26%. This grid interval dependency is in part due to changes in terrain height and slope angles in conjunction with the increased density of grid points. This dependency is also a function of energy propagation across a finite-difference grid.Sponsored by NSF ATM-9306754

Visualizing Energy Efficiency: A Picture is Worth More Than 1,022 Words

We deploy a randomized controlled trial involving approximately 12,500 householdsshowing that providing consumers with a visual depiction of heat loss on utility bills leads toconsiderably larger energy savings compared to a popular social comparison “nudge”. Imagesshowing roof heat loss were provided to approximately 4,000 randomly selected householdsin on-bill messaging. Heat loss is visualized using infrared images taken from an aircraft-mounted infrared sensor during the winter heating season. A similarly-sized randomlyselected group received bill messaging with a ‘traditional’ social norm comparing theirconsumption to similar homes. We also find that the heat loss treatment results in a higherrate of realized energy efficiency durables investment and leads households to conserve in amanner consistent with private and social efficiency: the most inefficient households exhibitmuch larger energy reductions relative to the traditional social comparison

Energy Codes and the Landlord-Tenant Problem

I estimate the energy efficiency premium in unlabeled office buildings by exploiting variation in mandatory building energy standard implementations, as a result of the U.S. 1992 Energy Policy Act. A more stringent energy code leads to rent and price premiums of approximately 4% and 9%, respectively. Significant heterogeneity in the rent premium is observed based on who pays the utility bills, as would be expected absent asymmetric information about energy conservation characteristics among real estate market participants. The rent and price premiums are larger in hotter, more humid climates, and are consistent with full capitalization of the energy savings from a more stringent standard

Pre-Labeling Market Valuations in the U.S. Green Building Stock and the Causal Effect of Green Labels

While green-labeled buildings have been found to sell at a premium compared to nearby controls with similar observable characteristics, the voluntary nature of the labeling decision implies green-labeled buildings may have different unmeasured characteristics that may account for at least a portion of the premium. Therefore, it is unclear whether green-labeled building premiums are a causal effect of the labels. I use data on repeat sales transactions and detailed hedonic characteristics to test whether green-labeled office buildings were selling at a premium before they were labeled, and combine these results with post-labeling price premium estimates to identify realized cost-benefit ratios for green-labeling policies. The data suggest the causal net benefits of green labels range from $11.50-$19.95 per square foot. The estimated net benefits are smaller than previous estimates that have focused solely on the benefits and ignored the potential biases from nonrandom selection

Setting the Standard: Commercial Electricity Consumption Responses to Energy Codes

The adoption rate of building energy standards in the US has been increasing since the mid- 1990s as a result of the Energy Policy Act of 1992 (EPAct). However, most of the evidence on the energy savings that accrue from commercial building energy standards is based on engineering simulations, which do not account for realized behavior once a standard is actually adopted. This paper uses plausibly exogenous variation in commercial building energy standard adoptions, combined with a unique state-level dataset on electricity consumption, energy prices, and the prevalence of “plus-utilities” tenancy contracts in commercial buildings, to estimate the realized electricity consumption response to commercial energy codes. The results suggest that in states with a large fraction of post-EPAct new construction under a code, per capita commercial electricity consumption is lower by about 13%. In addition, a one percentage point increase in the rate of tenancy contracts where tenants pay directly for energy utilities is associated with a 1% decrease in per capita electricity demand. The realized energy savings are less than half of predicted simulated savings

Fossil biomass preserved as graphitic carbon in a late paleoproterozoic banded iron formation metamorphosed at more than 550°C

Metamorphism is thought to destroy microfossils, partly through devolatilization and graphitization of biogenic organic matter. However, the extent to which there is a loss of molecular, elemental and isotope signatures from biomass during high-temperature metamorphism is not clearly established. We report on graphitic structures inside and coating apatite grains from the c. 1850 Ma Michigamme silicate banded iron formation from Michigan, metamorphosed above 550°C. Traces of N, S, O, H, Ca and Fe are preserved in this graphitic carbon and X-ray spectra show traces of aliphatic groups. Graphitic carbon has an expanded lattice around 3.6 Å, forms microscopic concentrically-layered and radiating polygonal flakes and has homogeneous δ13C values around −22‰, identical to bulk analyses. Graphitic carbon inside apatite is associated with nanometre-size ammoniated phyllosilicate. Precursors of these metamorphic minerals and graphitic carbon originated from ferruginous clayrich sediments with biomass. We conclude that graphite coatings and inclusions in apatite grains indicate fluid remobilization during amphibolite-facies metamorphism of precursor biomass. This new evidence fills in observational gaps of metamorphosed biomass into graphite and supports the existence of biosignatures in the highly metamorphosed iron formation from the Eoarchean Akilia Association, which dates from the beginning of the sedimentary rock record

Supersymmetry and R-symmetry breaking in models with non-canonical Kahler potential

We analyze several aspects of R-symmetry and supersymmetry breaking in generalized O'Raifeartaigh models with non-canonical Kahler potential. Some conditions on the Kahler potential are derived in order for the non-supersymmetric vacua to be degenerate. We calculate the Coleman-Weinberg (CW) effective potential for general quiral non-linear sigma models and then study the 1-loop quantum corrections to the pseudo-moduli space. For R-symmetric models, the quadratic dependence of the CW potential with the ultraviolet cutoff scale disappears. We also show that the conditions for R-symmetry breaking are independent of this scale and remain unchanged with respect to those of canonical models. This is, R-symmetry can be broken when generic R-charge assignments to the fields are made, while it remains unbroken when only fields with R-charge 0 and 2 are present. We further show that these models can keep the runaway behavior of their canonical counterparts and also new runaway directions can be induced. Due to the runaway directions, the non-supersymmetric vacua is metastable.Comment: 19 pages, revised version with minor changes, references added, published in JHE

Finite temperature behaviour of the ISS-uplifted KKLT model

We study the static phase structure of the ISS-KKLT model for moduli stabilisation and uplifting to a zero cosmological constant. Since the supersymmetry breaking sector and the moduli sector are only gravitationally coupled, we expect negligible quantum effects of the modulus upon the ISS sector, and the other way around. Under this assumption, we show that the ISS fields end up in the metastable vacua. The reason is not only that it is thermally favoured (second order phase transition) compared to the phase transition towards the supersymmetric vacua, but rather that the metastable vacua form before the supersymmetric ones. This nice feature is exclusively due to the presence of the KKLT sector. We also show that supergravity effects are negligible around the origin of the field space. Finally, we turn to the modulus sector and show that there is no destabilisation effect coming from the ISS sector.Comment: 23 pages, 3 figures, mistake corrected, one plot updated, physical conclusions unchange

Context Dependence, MOPs,WHIMs and procedures Recanati and Kaplan on Cognitive Aspects in Semantics

After presenting Kripke’s criticism to Frege’s ideas on context dependence of thoughts, I present two recent attempts of considering cognitive aspects of context dependent expressions inside a truth conditional pragmatics or semantics: Recanati’s non-descriptive modes of presentation (MOPs) and Kaplan’s ways of having in mind (WHIMs). After analysing the two attempts and verifying which answers they should give to the problem discussed by Kripke, I suggest a possible interpretation of these attempts: to insert a procedural or algorithmic level in semantic representations of indexicals. That a function may be computed by different procedures might suggest new possibilities of integrating contextual cognitive aspects in model theoretic semanti

Utilities Included: Split Incentives in Commercial Electricity Contracts

The largest decile of commercial electricity customers comprises half of commercial sector electricity usage. We quantify a substantial split incentives problem that exists when these large firms are on electricity-included property lease contracts. Using exogenous variation in weather shocks, we show that customers on tenant-paid contracts use 6-14% less electricity in summer months. The policy implications are promising. Nationwide energy savings from aligning incentives for the largest 10% of commercial customers exceeds analogous savings from the entire residential electricity sector. It is also cost-effective: switching to tenant-paid contracts via sub-metering has a private payoff period of under one year