Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Efthymios Serpetzoglou x
  • All content x
Clear All Modify Search
Efthymios Serpetzoglou, Bruce A. Albrecht, Pavlos Kollias, and Christopher W. Fairall

Abstract

The southeast Pacific stratocumulus regime is an important component of the earth’s climate system because of its substantial impact on albedo. Observational studies of this cloud regime have been limited, but during the past 5 yr, a series of cruises with research vessels equipped with in situ and remote sensing systems have provided unprecedented observations of boundary layer cloud and drizzle structures. These cruises started with the East Pacific Investigation of Climate (EPIC) 2001 field experiment, followed by cruises in a similar area in 2003 and 2004 [Pan-American Climate Studies (PACS) Stratus cruises]. The sampling from these three cruises provides a sufficient dataset to study the variability occurring over this region. This study compares observations from the 2004 cruise with those obtained during the previous two cruises. Observations from the ship provide information about boundary layer structure, fractional cloudiness, cloud depth, and drizzle characteristics. This study indicates more strongly decoupled boundary layers during the 2004 cruise than the well-mixed conditions that dominated the cloud and boundary layer structures during the EPIC cruise, and the highly variable conditions—sharp transitions from a solid stratus deck to broken-cloud and clear-sky periods—encountered during PACS Stratus 2003. Diurnal forcing and synoptic conditions are considered to be factors affecting these variations. A statistical evaluation of the macrophysical boundary layer, cloud, and drizzle properties is performed using the 5–6-day periods for which the research vessels remained stationed at the location of 20°S, 85°W during each cruise.

Full access
Efthymios Serpetzoglou, Emmanouil N. Anagnostou, Anastasios Papadopoulos, Efthymios I. Nikolopoulos, and Viviana Maggioni

Abstract

The study presents an in-depth investigation of the properties of remotely sensed rainfall error propagation in the prediction of near-surface soil moisture from a land surface model (LSM). Specifically, two error sources are compared: rainfall forcing due to estimation error by remote sensing techniques and the representation of land–atmospheric processes due to LSM uncertainty [the Community Land Model, version 3.5 (CLM3.5), was used in this particular study]. CLM3.5 is forced by three remotely sensed precipitation products, namely, two satellite-based estimates—NASA’s Tropical Rainfall Measuring Mission (TRMM) multisatellite precipitation analysis and NOAA’s Climate Prediction Center morphing technique (CMORPH)—and a rain gauge-adjusted radar–rainfall product from the Weather Surveillance Radar-1988 Doppler (WSR-88D) network. The error analysis is performed for the warm seasons of 2004 and 2006 and is facilitated through the use of in situ measurements of soil moisture, rainfall, and other meteorological variables from a network of stations capturing the state of Oklahoma (Oklahoma Mesonet). The study also presents a rigorous benchmarking of the Mesonet network as to its accuracy in deriving area rainfall estimates at the resolution of satellite products (0.25° and 3 h) through comparisons against the most definitive measurements of a smaller-yet-denser network of rain gauges in southwestern Oklahoma (Micronet). The study compares error statistics between modeling and precipitation error sources and between the various remote sensing techniques. Results are contrasted between the relatively moist summer period of 2004 to the drier summer period of 2006, indicating model and error propagation dependencies. An intercomparison between rainfall and modeling error shows that the two error sources are of similar magnitudes in the case of high modeling accuracy (i.e., 2004), whereas the contribution of rainfall forcing error to the uncertainty of soil moisture prediction can be lower when the model’s efficiency skill is relatively low (i.e., 2006).

Full access
Robert M. Rauber, Bjorn Stevens, Jennifer Davison, Sabine Goke, Olga L. Mayol-Bracero, David Rogers, Paquita Zuidema, Harry T. Ochs III, Charles Knight, Jorgen Jensen, Sarah Bereznicki, Simona Bordoni, Humberto Caro-Gautier, Marilé Colón-Robles, Maylissa Deliz, Shaunna Donaher, Virendra Ghate, Ela Grzeszczak, Colleen Henry, Anne Marie Hertel, Ieng Jo, Michael Kruk, Jason Lowenstein, Judith Malley, Brian Medeiros, Yarilis Méndez-Lopez, Subhashree Mishra, Flavia Morales-García, Louise A. Nuijens, Dennis O'Donnell, Diana L. Ortiz-Montalvo, Kristen Rasmussen, Erin Riepe, Sarah Scalia, Efthymios Serpetzoglou, Haiwei Shen, Michael Siedsma, Jennifer Small, Eric Snodgrass, Panu Trivej, and Jonathan Zawislak

The Rain in Cumulus over the Ocean (RICO) field campaign carried out a wide array of educational activities, including a major first in a field project—a complete mission, including research flights, planned and executed entirely by students. This article describes the educational opportunities provided to the 24 graduate and 9 undergraduate students who participated in RICO.

Full access