Climate Monitoring and Diagnostics Laboratory

About: Climate Monitoring and Diagnostics Laboratory is a based out in . It is known for research contribution in the topics: Aerosol & Stratosphere. The organization has 107 authors who have published 263 publications receiving 26434 citations.

Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze

Abstract: Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects. The haze particles consisted of several inorganic and carbonaceous species, including absorbing black carbon clusters, fly ash, and mineral dust. The most striking result was the large loading of aerosols over most of the South Asian region and the North Indian Ocean. The January to March 1999 visible optical depths were about 0.5 over most of the continent and reached values as large as 0.2 over the equatorial Indian ocean due to long-range transport. The aerosol layer extended as high as 3 km. Black carbon contributed about 14% to the fine particle mass and 11% to the visible optical depth. The single-scattering albedo estimated by several independent methods was consistently around 0.9 both inland and over the open ocean. Anthropogenic sources contributed as much as 80% (±10%) to the aerosol loading and the optical depth. The in situ data, which clearly support the existence of the first indirect effect (increased aerosol concentration producing more cloud drops with smaller effective radii), are used to develop a composite indirect effect scheme. The Indo-Asian aerosols impact the radiative forcing through a complex set of heating (positive forcing) and cooling (negative forcing) processes. Clouds and black carbon emerge as the major players. The dominant factor, however, is the large negative forcing (-20±4 W m^(−2)) at the surface and the comparably large atmospheric heating. Regionally, the absorbing haze decreased the surface solar radiation by an amount comparable to 50% of the total ocean heat flux and nearly doubled the lower tropospheric solar heating. We demonstrate with a general circulation model how this additional heating significantly perturbs the tropical rainfall patterns and the hydrological cycle with implications to global climate.

Determining Aerosol Radiative Properties Using the TSI 3563 Integrating Nephelometer

Abstract: Methods for reducing and quantifying the uncertainties in aerosol optical properties measured with the TSI 3563 integrating nephelometer are presented. For nearly all applications, the recommended calibration gases are air and CO2. By routinely characterizing the instrumental response to these gases, a diagnostic record of instrument performance can be created. This record can be used to improve measurement accuracy and quantify uncertainties due to instrumental noise and calibration drift. When measuring scattering by particles, size segregation upstream of the nephelometer at about 1 μm aerodynamic diameter greatly increases the information content of the data for two reasons: one stemming from the independence of coarse and fine particles in the atmosphere, and the second stemming from the size dependence of the nephelometer response. For many applications (e.g., extinction budget studies) it is important to correct nephelometer data for the effects of angular nonidealities. Correction factors...

Surface Climate Variations over the North Atlantic Ocean during Winter: 1900–1989

Abstract: The low-frequency variability of the surface climate over the North Atlantic during winter is described, using 90 years of weather observations from the Comprehensive Ocean–Atmosphere Data Set. Results are based on empirical orthogonal function analysis of four components of the climate system: sea surface temperature (SST), air temperature, wind, and sea level pressure. An important mode of variability of the wintertime surface climate over the North Atlantic during this century is characterized by a dipole pattern in SSTs and surface air temperatures, with anomalies of one sign cast of Newfoundland, and anomalies of the opposite polarity off the southeast coast of the United States. Wind fluctuations occur locally over the regions of large surface temperature anomalies, with stronger-than-normal winds overlying cooler-than-normal SSTs. This mode exhibits variability on quasi-decadal and biennial time scales. The decadal fluctuations are irregular in length, averaging ∼9 years before 1945 and ∼1...