APHRODITE's SCOPE

APHRODITE's Goals

  • Release official state-of-the-art daily grid precipitation datasets that are based on rain-gauge observations.
  • Assess the projections of climate models by observing precipitation in the field, including extreme events.
  • Make suggestions to regional water resources managers in Asian countries.


APHRODITE's Point of View

  • The grid data will primarily be developed from the analysis of long-term, rain-gauge-based observations.
  • Orographic precipitation will be explicitly reproduced by making efforts to reproduce precipitation climatology with orographic effects.
  • Satellite and radar observation data will be used to develop interpolation methods as well as to develop climatological datasets.
  • Datasets will be developed in collaboration with climate modelers. We will consider the requests of modelers and may use model data to improve our methods.

Background

The distribution of precipitation is generally considered to be largely modulated by orographic effects. There are some significant mountainous regions in Asia, such as the Himalayas and the Tibetan Plateau. To a large extent, the distribution of precipitation also appears to be modulated by climate change. Therefore, understanding and quantifying orographic precipitation is of fundamental importance to assessing the regional impact of global warming.

The regional impacts of global climate change are reported in greater detail in the 2007 Report of the Intergovernmental Panel on Climate Change (IPCC) than they are in the 2001 report. One reason for the change is that the IPCC has responded to the needs of local policymakers, and another is the improved resolution of climate models. Empirical and statistical methods are being used for making regional projections of the impacts of global warming. They are also effective as a downscaling method for orographic precipitation models, which do not have straightforward dynamic and parameterization processes. However, statistical downscaling has been applied only to regions for which sufficient observational datasets are available. Thus, acquiring the observational rainfall datasets is crucially important for statistical downscaling as well as for verifying high-resolution climate model simulations.

Scientific Objectives

We have two sub-thematic programs: (1) development of the daily grid precipitation datasets and (2) validation of General Circulation Models against the grid datasets. In these programs, we focus on the following objectives:

  1. Develop the daily grid datasets from gauge-based observational records.
  2. Improve the quantification of orographic precipitation by using a combination of rain-gauge data, remotely sensed data, and geographic information (e.g., topography).
  3. Validate climate models against the grid datasets that are developed in Objectives 1 and 2, and assess the models' performance.
  4. Critically assess statistics of the daily datasets and interpolation methods.
  5. Characterize temporal and spatial variability in precipitation and in water resources.

Project Term

This project was started in May 2006 and will continue through March 2011.