Maximization of Historical Storm Events over Seven Watersheds in Central/Southern Sierra Nevada by Means of Atmospheric Boundary Condition Shifting and Relative Humidity Optimization Methods

2022 ◽  
Vol 27 (3) ◽  
Author(s):  
Toan Trinh ◽  
Yoshihiko Iseri ◽  
Andres J. Diaz ◽  
Emily D. Snider ◽  
Michael L. Anderson ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Relative Humidity ◽  
Sierra Nevada ◽  
Optimization Methods ◽  
Storm Events

scholarly journals Validation and Sensitivities of Dynamic Precipitation Simulation for Winter Events over the Folsom Lake Watershed: 1964–99

2005 ◽  
Vol 133 (1) ◽  
pp. 3-19 ◽  
Author(s):  
Jianzhong Wang ◽  
Konstantine P. Georgakakos
Keyword(s):  
Sierra Nevada ◽  
Mesoscale Model ◽  
Pilot Project ◽  
Storm Events ◽  
Bias Score ◽  
Warm Start ◽  
Precipitation Simulation ◽  
Simulated Precipitation ◽  
Precipitation Gauge ◽  
Folsom Lake

Abstract A total of 62 winter-storm events in the period 1964–99 over the Folsom Lake watershed located at the windward slope of the Sierra Nevada were simulated with a 9-km resolution using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). Mean areal precipitation (MAP) over the entire watershed and each of four subbasins was estimated based on gridded simulated precipitation. The simulated MAP was verified with MAP estimated (a) by the California Nevada River Forecast Center (CNRFC) for the four subbasins based on eight operational precipitation stations, and (b) for the period from 1980 to 1986, on the basis of a denser precipitation observing network deployed by the Sierra Cooperative Pilot Project (SCPP). A number of sensitivity runs were performed to understand the dependence of model precipitation on boundary and initial fields, cold versus warm start, and microphysical parameterization. The principal findings of the validation analysis are that (a) MM5 achieves a good percentage bias score of 103% in simulating Folsom basin MAP when compared to MAP derived from dense precipitation gauge networks; (b) spatial grid resolution higher than 9 km is necessary to reproduce the spatial MAP pattern among subbasins of the Folsom basin; and (c) the model performs better for heavy than for light and moderate precipitation. The analysis also showed significant simulation dependence on the spatial resolution of the boundary and initial fields and on the microphysical scheme used.

scholarly journals Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in situ instrumentation

2018 ◽  
Vol 18 (10) ◽  
pp. 7001-7017 ◽  
Author(s):  
Andrés Esteban Bedoya-Velásquez ◽  
Francisco Navas-Guzmán ◽  
María José Granados-Muñoz ◽  
Gloria Titos ◽  
Roberto Román ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Relative Humidity ◽  
Sierra Nevada ◽  
Microwave Radiometer ◽  
Growth Parameter ◽  
Horizontal Wind ◽  
Hygroscopic Growth ◽  
Backscatter Coefficient ◽  
532 Nm

Abstract. This study focuses on the analysis of aerosol hygroscopic growth during the Sierra Nevada Lidar AerOsol Profiling Experiment (SLOPE I) campaign by using the synergy of active and passive remote sensors at the ACTRIS Granada station and in situ instrumentation at a mountain station (Sierra Nevada, SNS). To this end, a methodology based on simultaneous measurements of aerosol profiles from an EARLINET multi-wavelength Raman lidar (RL) and relative humidity (RH) profiles obtained from a multi-instrumental approach is used. This approach is based on the combination of calibrated water vapor mixing ratio (r) profiles from RL and continuous temperature profiles from a microwave radiometer (MWR) for obtaining RH profiles with a reasonable vertical and temporal resolution. This methodology is validated against the traditional one that uses RH from co-located radiosounding (RS) measurements, obtaining differences in the hygroscopic growth parameter (γ) lower than 5 % between the methodology based on RS and the one presented here. Additionally, during the SLOPE I campaign the remote sensing methodology used for aerosol hygroscopic growth studies has been checked against Mie calculations of aerosol hygroscopic growth using in situ measurements of particle number size distribution and submicron chemical composition measured at SNS. The hygroscopic case observed during SLOPE I showed an increase in the particle backscatter coefficient at 355 and 532 nm with relative humidity (RH ranged between 78 and 98 %), but also a decrease in the backscatter-related Ångström exponent (AE) and particle linear depolarization ratio (PLDR), indicating that the particles became larger and more spherical due to hygroscopic processes. Vertical and horizontal wind analysis is performed by means of a co-located Doppler lidar system, in order to evaluate the horizontal and vertical dynamics of the air masses. Finally, the Hänel parameterization is applied to experimental data for both stations, and we found good agreement on γ measured with remote sensing (γ532=0.48±0.01 and γ355=0.40±0.01) with respect to the values calculated using Mie theory (γ532=0.53±0.02 and γ355=0.45±0.02), with relative differences between measurements and simulations lower than 9 % at 532 nm and 11 % at 355 nm.

scholarly journals Two optimization methods for solving the inverse gravimetrical problem

2021 ◽  
Vol 2092 (1) ◽  
pp. 012017
Author(s):  
Merey Kenzhebayeva
Keyword(s):  
Boundary Condition ◽  
Inverse Problem ◽  
Numerical Analysis ◽  
Gravity Field ◽  
Gradient Method ◽  
Optimization Problems ◽  
Mineral Exploration ◽  
Optimization Methods ◽  
The Earth

Abstract Mineral exploration, in particular, increasing the accuracy of calculations up to now is one of the urgent problems of geophysics. It is necessary to restore the density of a given inhomogeneity after considering the results of measuring the potential and its gradient on the surface of the earth. One of the measured values, the potential or the gradient of the gravity field, is chosen beyond the boundary condition, and the second corresponds to the minimized functional, i.e. one in-verse problem can be put in correspondence two different optimization problems. Both problems are solved based on the same gradient method. Based on the numerical analysis, two methods for solving the inverse problem are compared.

High-Elevation Precipitation Patterns: Using Snow Measurements to Assess Daily Gridded Datasets across the Sierra Nevada, California*

2015 ◽  
Vol 16 (4) ◽  
pp. 1773-1792 ◽  
Author(s):  
Jessica D. Lundquist ◽  
Mimi Hughes ◽  
Brian Henn ◽  
Ethan D. Gutmann ◽  
Ben Livneh ◽  
...  
Keyword(s):  
United States ◽  
Water Resources ◽  
Atmospheric Circulation ◽  
Sierra Nevada ◽  
The United States ◽  
High Elevation ◽  
Precipitation Gradient ◽  
Storm Events ◽  
Total Water ◽  
The West

Abstract Gridded spatiotemporal maps of precipitation are essential for hydrometeorological and ecological analyses. In the United States, most of these datasets are developed using the Cooperative Observer (COOP) network of ground-based precipitation measurements, interpolation, and the Parameter–Elevation Regressions on Independent Slopes Model (PRISM) to map these measurements to places where data are not available. Here, we evaluate two daily datasets gridded at ° resolution against independent daily observations from over 100 snow pillows in California’s Sierra Nevada from 1990 to 2010. Over the entire period, the gridded datasets performed reasonably well, with median total water-year errors generally falling within ±10%. However, errors in individual storm events sometimes exceeded 50% for the median difference across all stations, and in many cases, the same underpredicted storms appear in both datasets. Synoptic analysis reveals that these underpredicted storms coincide with 700-hPa winds from the west or northwest, which are associated with post-cold-frontal flow and disproportionately small precipitation rates in low-elevation valley locations, where the COOP stations are primarily located. This atmospheric circulation leads to a stronger than normal valley-to-mountain precipitation gradient and underestimation of actual mountain precipitation. Because of the small average number of storms (<10) reaching California each year, these individual storm misses can lead to large biases (~20%) in total water-year precipitation and thereby significantly affect estimates of statewide water resources.

scholarly journals Topographically Generated Cloud Plumes

2006 ◽  
Vol 134 (8) ◽  
pp. 2108-2127 ◽  
Author(s):  
Qingfang Jiang ◽  
James D. Doyle
Keyword(s):  
Relative Humidity ◽  
Sierra Nevada ◽  
Rocky Mountain ◽  
Real Data ◽  
Ice Crystals ◽  
Small Crystals ◽  
Modis Image ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Moist Layer

Abstract Two topographically generated cirrus plume events have been examined through satellite observations and real-data simulations. On 30 October 2002, an approximately 70-km-wide cirrus plume, revealed by a high-resolution Moderate Resolution Imaging Spectroradiometer (MODIS) image and a series of Geostationary Operational Environmental Satellite (GOES) images, originated from the Sierra Nevada ridge and extended northeastward for more than 400 km. On 5 December 2000, an approximately 400-km-wide cloud plume originated from the Southern Rocky Mountain massif and extended eastward for more than 500 km, the development of which was captured by a series of GOES images. The real-data simulations of the two cirrus plume events successfully capture the presence of these plumes and show reasonable agreement with the MODIS and GOES images in terms of the timing, location, orientation, length, and altitude of these cloud plumes. The synoptic and mesoscale aspects of the plume events, and the dynamics and microphysics relevant to the plume formation, have been discussed. Two common ingredients relevant to the cirrus plume formation have been identified, namely, a relatively deep moist layer aloft with high relative humidity and low temperature (≤−40°C near the cloud top), and strong updrafts over high terrain and slow descent downstream in the upper troposphere associated with terrain-induced inertia–gravity waves. The rapid increase of the relative humidity associated with strong updrafts creates a high number concentration of small ice crystals through homogeneous nucleation. The overpopulated ice crystals decrease the relative humidity, which, in return, inhibits small crystals from growing into large crystals. The small crystals with slow terminal velocities (<0.2 m s−1) can be advected hundreds of kilometers before falling out of the moist layer.

Uncertainty in Probable Maximum Precipitation for Dam Safety 

2021 ◽  
Author(s):  
Emilie Tarouilly ◽  
Dennis Lettenmaier
Keyword(s):  
Relative Humidity ◽  
Wrf Model ◽  
Atmospheric Model ◽  
Dam Safety ◽  
Large Network ◽  
Storm Events ◽  
Probable Maximum Precipitation ◽  
Sources Of Uncertainty ◽  
Maximum Precipitation ◽  
Model Based

<p>California’s large network of dams is under increasing scrutiny as hydrologic extremes are becoming more frequent and dams are aging. Typically, dam spillways are sized for the most severe flood that is likely in a given watershed, called the Probable Maximum Flood (PMF). PMF is obtained from the Probable Maximum Precipitation (PMP), which is the greatest 72-hour depth of precipitation that is “meteorologically probable”. Historically, PMP has been estimated by scaling depth-area-duration relationships obtained from severe historical storms. The scaling factor was estimated as the ratio of moisture available during that storm to the climatological maximum for the region. This PMP estimation approach, after which the spillways of most existing dams in California have been sized, has long been criticized as being somewhat arbitrary, although in practice it has led to relatively conservative spillway designs. Advances in both atmospheric models now facilitate a more rational basis for specifying PMP. Over the last decade, model-based PMP estimation frameworks have been developed whereby a severe historical storm is reconstructed and “maximized” using a regional atmospheric model. The most common approach to date, called relative humidity maximization (RHM) consists of setting relative humidity to 100% at the model boundaries, which has the effect of generating more precipitation (“maximum”) than occurred in the actual storm. This addresses major limitations of earlier PMP techniques through (1) more realistic representation of storm physics, (2) applicability of the method to future climate, and (3) suitability for forcing hydrologic models for improved PMF estimation.</p><p>The work I present here addresses concerns regarding the sources of uncertainty in the RHM approach, such as choice of storm to reconstruct and maximize, and choice of model physics parametrizations that directly affect model-based PMP estimates. To do so I produce an ensemble of PMP estimates (rather than a single value) that samples the above-mentioned sources of uncertainty. I focus on three California study basins, all of which have large reservoirs and different topographic and hydroclimatic conditions: the Feather, Russian and Santa Ana River basins. Using the WRF model forced with ERA5 reanalysis, I first create an ensemble of 40 reconstructions based on 10 combinations of physics parametrizations for 4 severe historical storms (Dec. 1964, Feb. 1986, Jan. 1997, and Feb. 2019). Next, I modify the 40 reconstructions by maximizing the model boundary moisture fluxes. This results in an ensemble of 4 storm events, 10 physics combinations, and 2 PMP methods, yielding 80 PMP estimates from which to better assess uncertainty in PMP. Differences among the PMP estimates I obtain based on different storm events, model physics and PMP methods confirm the value of such an ensemble in providing a measure of uncertainty in PMP estimates . Focusing on large dams in California, this work is intended to improve confidence in and utility of PMP estimates, which form the cornerstone of dam safety, and ultimately enable safer and more effective reservoir management as the climate continues to change.</p>

scholarly journals Boundary conditions for the problem of moisture transport in concrete

2021 ◽  
Vol 263 ◽  
pp. 03014
Author(s):  
Zaven Ter-Martirosyan ◽  
Viktor Bakhmisov
Keyword(s):  
Boundary Condition ◽  
Relative Humidity ◽  
Boundary Conditions ◽  
Moisture Transport ◽  
Water Pressure ◽  
Degree Of Saturation ◽  
Poor Correlation ◽  
Soil Environment ◽  
Environment Temperature ◽  
Hydrus 1D

When calculating of the moisture transport in concrete of such geotechnical structures as a pile or diaphragm wall, contact with soil is forming the special boundary conditions. If the soil is in the full saturated state, then the Darcy’s law should be used to solve the problem, the boundary condition for which is the water pressure. Otherwise, the Bažant- Najjar model is used, for which the boundary condition is the relative humidity of soil environment at a certain temperature. The soil environment temperature is unique characteristic for each construction area. For Moscow region, the weighted arithmetic mean temperature to the depth of 60 m is 7.3°C. It is proposed to calculate the relative humidity of the soil environment according to the Kelvin capillary condensation equation, in which the suction is calculated using the Mualem-van Genuchten hydraulic model from the degree of saturation. Two well- known sets of hydraulic parameters of the Mualem-van Genuchten model, compiled on the HYPRES and the HYDRUS-1D database from the European soil map texture classes and the USDA textural soil classification respectively, were compared with the measurement results for soil samples classified according to Russian the GOST 25100. The experimental data showed a good approximation to the calculation with a set of parameters obtained on the basis of the HYPRES database. At the same time, the solution with the HYDRUS-1D parameter set showed a poor correlation.

Effect Of Surface Boundary Condition On Rainfall Infiltration

2012 ◽  
Author(s):  
Nurly Gofar ◽  
Min Lee Lee ◽  
Azman Kassim
Keyword(s):  
Boundary Condition ◽  
Wind Speed ◽  
Hydraulic Conductivity ◽  
Relative Humidity ◽  
Soil Temperature ◽  
Soil Column ◽  
Rainfall Infiltration ◽  
Surface Boundary ◽  
Ambient Temperatures ◽  
Surface Boundary Condition

Penyusupan air hujan amat dipengaruhi oleh keadaan sempadan permukaan tanah dan sifat–sifat hidraulik tanah. Kertas kerja ini mengetengahkan kajian mengenai kesan beberapa keadaan sempadan permukaan tanah terhadap penyusupan air hujan dengan menggunakan satu program komputer VADOSE/W. Satu kajian parametrik dijalankan untuk mengkaji kesan suhu persekitaran, kelembapan relatif udara, dan kelajuan angin terhadap penyejatan dan kadar penyusupan air hujan. Kesan konduktiviti hidraulik tanah terhadap mekanisma penyusupan air hujan juga dikaji dengan menggunakan dua model tiang tanah. Keputusan menunjukkan penyusupan air hujan adalah sensitif terhadap kelembapan relatif udara dan suhu persekitaran yang lebih rendah daripada suhu tanah, tetapi tidak sensitif terhadap kelajuan angin dan suhu persekitaran yang lebih tinggi daripada suhu tanah. Konduktiviti hidraulik tanah dan keamatan hujan mempunyai pengaruh yang besar terhadap mekanisme penyusupan dan pembentukan air larian permukaan. Maka, profil ketepuan tanah yang meyakinkan hanya boleh diperolehi jika keadaan sempadan permukaan tanah yang tepat dipertimbangkan dalam analisis. Kata kunci: Penyusupan air hujan, penyejatan, keadaan sempadan, konduktiviti hidraulik, model tiang tanah Rainfall infiltration is greatly influenced by the surface boundary condition as well as hydraulic properties of soil. This paper highlights the study on the effect of several surface boundary conditions on the rainfall infiltration using a computer program VADOSE/W. A parametric study was carried out to study the effect of ambient temperature, relative humidity and wind speed on the evaporation and rainfall infiltration rate. The effect of soil hydraulic conductivity on the mechanism of rainfall infiltration was also studied by using two soil column models. Results show that rainfall infiltration is sensitive to relative humidity and ambient temperatures lower than soil temperature, but insensitive to wind speed and ambient temperatures higher than soil temperature. The hydraulic conductivity of soil and rainfall intensity have great influence on the infiltration mechanism and the development of surface runoff. Thus, reliable saturation profile can only be achieved if accurate surface boundary condition was considered for analysis. Key words: Rainfall infiltration, evaporation, boundary condition, hydraulic conductivity, soil column model

scholarly journals Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in-situ instrumentation

2017 ◽  
Author(s):  
Andrés E. Bedoya-Velásquez ◽  
Francisco Navas-Guzmán ◽  
María J. Granados-Muñoz ◽  
Gloria Titos ◽  
Roberto Roman ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Relative Humidity ◽  
Sierra Nevada ◽  
Atmospheric Stability ◽  
Growth Parameter ◽  
Horizontal Wind ◽  
High Temporal Resolution ◽  
Hygroscopic Growth ◽  
532 Nm

Abstract. This work focuses on the study of aerosol hygroscopic growth during Sierra Nevada Lidar AerOsol Profiling Experiment (SLOPE I) campaign by using the synergy of active and passive remote sensors at Granada valley station (IISTA-CEAMA station) and in-situ instrumentation at a mountain station (Sierra Nevada station, SNS), located ~ 20 km away from IISTA-CEAMA and about 1 km above this station. To this end, a methodology based on the combination of calibrated water vapour mixing ratio (r) profiles, retrieved from an EARLINET multiwavelength Raman lidar (RL), and continuous temperature profiles from a microwave radiometer (MWR) for obtaining relative humidity (RH) profiles with high temporal resolution is used. This methodology is validated against an approach using radiosounding (RS) data at the EARLINET IISTA-CEAMA station, achieving differences in hygroscopic growth parameter (γ) lower than 5 % between the methodology based on RS and that based on remote sensing. During SLOPE I the remote sensing methodology used for aerosol hygroscopic growth studies has been checked using Mie calculations with in-situ measurements at SNS. For SLOPE I case with remote sensing instrumentation, an increase in particle backscatter coefficient at 355 and 532 nm is observed from 1.5 to 2.4 km a.s.l. in the relative humidity range of 78–98 %, but also a decrease on Ångström exponent (AE) and particle linear depolarization ratio (PLDR). This fact indicates that particles become larger and more spherical as relative humidity increases, what is strongly related to aerosol hygroscopic growth. In addition, atmospheric stability is checked ensuring well-mixed layers. Vertical and horizontal wind analysis is performed by means of a co-located Doppler lidar system at IISTA-CEAMA station, in order to evaluate the horizontal and vertical dynamics of the air masses. Finally, the Hänel parameterization is applied to experimental data for both stations, obtaining relative differences between RL and Mie simulations up to 13 % and 10 % for 532 nm and 355 nm, respectively.

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